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    <title><![CDATA[[SecurityRatty] tag: pdfs]]></title>
    <link>http://securityratty.com/tag/pdfs</link>
    <description></description>
    <pubDate>Wed, 14 May 2008 11:50:22 +0000</pubDate>
    <generator>iRatty Engine</generator>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <item>
      <title><![CDATA[US Government Detects Attacks on Obama and McCain Computers]]></title>
      <link>http://securityratty.com/article/6097824d379ae9660e32fe10fd040b20</link>
      <guid>http://securityratty.com/article/6097824d379ae9660e32fe10fd040b20</guid>
      <description><![CDATA[Now that the presidential race is over Newsweek is reporting that the US Government, through the FBI and Secret Service, notified the Obama and McCain campaigns that their computers had been...]]></description>
      <content:encoded><![CDATA[<p>Now that the presidential race is over <a href="http://www.newsweek.com/id/167581">Newsweek is reporting</a> that the US Government, through the FBI and Secret Service, notified the Obama and McCain campaigns that their computers had been compromised and sensitive documents copied. </p>
<blockquote><p>&#8230;the FBI and the Secret Service came to the campaign with an ominous warning: &#8220;You have a problem way bigger than what you understand,&#8221; an agent told Obama&#8217;s team. &#8220;You have been compromised, and a serious amount of files have been loaded off your system.&#8221; The following day, Obama campaign chief David Plouffe heard from White House chief of staff Josh Bolten, to the same effect: &#8220;You have a real problem &#8230; and you have to deal with it.&#8221; The Feds told Obama&#8217;s aides in late August that the McCain campaign&#8217;s computer system had been similarly compromised.</p></blockquote>
<p>This information demonstrates that the US government has a sophisticated intrusion detection capability.  This is likely part of the <a href="http://www.spamdailynews.com/publish/ATT_tech_outs_NSA_spy_room.asp">NSA internet surveillance system</a> that was made public by an AT&#038;T technician in 2006.  </p>
<p><center><img alt="" src="http://www.spamdailynews.com/uploads/intercept-diagram-1.gif" class="photonoborder" width="432" height="233" /></center></p>
<p>It is likely that the system has a set of watch IP ranges that are sensitive from a national security perspective.  The campaigns&#8217; computers were probably on this list. The traffic between foreign IP addresses and these watch IPs is then scrutinized for espionage.  The pattern of activity flagged would be Microsoft Office documents and PDFs being retrieved or other intruder signs such as an encrypted tunnel with a foreign endpoint.</p>
<p>This shows that the US Government has the capability to detect some types foreign attacks although they probably have to be selective of the IP ranges they monitor.  It&#8217;s nice to know that if the White House computers were leaking documents to China or Russia that there is some detection capability, but the fact that this is done at the Internet backbone level means any IP could be targeted and it might not just be to look for foreign intrusions.</p>
]]></content:encoded>
      <pubDate>Fri, 07 Nov 2008 13:18:05 +0000</pubDate>
      <category domain="http://securityratty.com/tag/computers">computers</category>
      <category domain="http://securityratty.com/tag/intrusion detection capability">intrusion detection capability</category>
      <category domain="http://securityratty.com/tag/detection capability">detection capability</category>
      <category domain="http://securityratty.com/tag/foreign">foreign</category>
      <category domain="http://securityratty.com/tag/foreign intrusions">foreign intrusions</category>
      <category domain="http://securityratty.com/tag/sensitive">sensitive</category>
      <category domain="http://securityratty.com/tag/sensitive documents">sensitive documents</category>
      <category domain="http://securityratty.com/tag/documents">documents</category>
      <category domain="http://securityratty.com/tag/white house computers">white house computers</category>
      <source url="http://www.veracode.com/blog/2008/11/us-government-detects-attacks-on-obama-and-mccain-computers/">US Government Detects Attacks on Obama and McCain Computers</source>
    </item>
    <item>
      <title><![CDATA[PCI Compliance: Reaction to the Summary of Changes]]></title>
      <link>http://securityratty.com/article/ddeefb896f6d234b28dddac20a55a9c5</link>
      <guid>http://securityratty.com/article/ddeefb896f6d234b28dddac20a55a9c5</guid>
      <description><![CDATA[On August 18 the PCI Security Standards Council formally announced ( http://www.pcisecuritystandards.org/pdfs/08-18-08 2.pdf ) forthcoming changes to the Payment Card Industry's Data Security Standard...]]></description>
      <content:encoded><![CDATA[On August 18 the PCI Security Standards Council formally announced (<a href="http://www.pcisecuritystandards.org/pdfs/08-18-08_2.pdf" target=_blank>http://www.pcisecuritystandards.org/pdfs/08-18-08_2.pdf</a>) forthcoming changes to the Payment Card Industry's Data Security Standard (PCI DSS) as it moves from version 1.1 to version 1.2 in October 2008.  The release represents the first major update since September 2006.
<P>
What's my take on the summary of changes? <B>Most merchants will be pleased to see that these are relatively minor changes...</b>]]></content:encoded>
      <pubDate>Mon, 18 Aug 2008 20:00:00 +0000</pubDate>
      <category domain="http://securityratty.com/tag/payment card industry">payment card industry</category>
      <category domain="http://securityratty.com/tag/data security standard">data security standard</category>
      <category domain="http://securityratty.com/tag/release represents">release represents</category>
      <category domain="http://securityratty.com/tag/version">version</category>
      <category domain="http://securityratty.com/tag/pci dss">pci dss</category>
      <category domain="http://securityratty.com/tag/summary">summary</category>
      <category domain="http://securityratty.com/tag/october">october</category>
      <category domain="http://securityratty.com/tag/pdf">pdf</category>
      <category domain="http://securityratty.com/tag/minor">minor</category>
      <source url="http://www.rsa.com/blog/blog_entry.aspx?id=1330">PCI Compliance: Reaction to the Summary of Changes</source>
    </item>
    <item>
      <title><![CDATA[Apple Finally Patches DNS Bug]]></title>
      <link>http://securityratty.com/article/97bfbbeabb93754b8d92bca89e191539</link>
      <guid>http://securityratty.com/article/97bfbbeabb93754b8d92bca89e191539</guid>
      <description><![CDATA[After taking guff in the press for a while for their lack of a patch for the famous recent DNS bug, Apple has finally issued a patch. The update it comes in also patches 16 other vulnerabilities
Open...]]></description>
      <content:encoded><![CDATA[<a href="http://db.tidbits.com/article/9706">After taking guff in the press for a while</a> for their lack of a patch for the famous recent DNS bug, Apple has finally issued a patch. <a href="http://support.apple.com/kb/HT2647">The update it comes in also patches 16 other vulnerabilities.</a>

<ul>
	<li>Open Scripting Architecture&#151;Privilege elevation bug when loading plugins.</li>
	<li>CarbonCore&#151;A stack overflow in handling long file names. Potential code execution.</li>
	<li>CoreGraphics&#151;2 bugs, both code execution, one for malicious graphics the other for malicious PDFs.</li>
	<li>Data Detectors Engine&#151;Engine may crash when parsing maliciously crafted content.</li>
	<li>Disk Utility&#151;A local user may obtain System privileges.</li>
	<li>OpenLDAP&#151;An ASN parsing bug can lead to a crash.</li>
	<li>OpenSSL&#151;A range checking error from last September (Red Hat patched it in 2 weeks) can lead to remote code execution.</li>
	<li>PHP&#151;5 different bugs, the worst of which can lead to remote code execution. </li>
	<li>QuickLook&#151;A maliciously-crafted Microsoft Office file can cause QuickLooks to crash or allow remote code execution.</li>
	<li>rsync&#151;Path validation errors, which were also reported in 2007, are resolved.</li>
</ul><br style="clear: both;"/>
  <img alt="" style="border: 0; height:1px; width:1px;" border="0" src="http://www.pheedo.com/img.phdo?i=abf12a39094359c814fd385242a4a01a" height="1" width="1"/>
<img src="http://www.pheedo.com/feeds/tracker.php?i=abf12a39094359c814fd385242a4a01a" style="display: none;" border="0" height="1" width="1" alt=""/><img src="http://feeds.ziffdavisenterprise.com/~r/RSS/cheap_hack/~4/352198240" height="1" width="1"/>]]></content:encoded>
      <pubDate>Thu, 31 Jul 2008 19:12:34 +0000</pubDate>
      <category domain="http://securityratty.com/tag/code execution">code execution</category>
      <category domain="http://securityratty.com/tag/remote code execution">remote code execution</category>
      <category domain="http://securityratty.com/tag/bug">bug</category>
      <category domain="http://securityratty.com/tag/potential code execution">potential code execution</category>
      <category domain="http://securityratty.com/tag/lead">lead</category>
      <category domain="http://securityratty.com/tag/data detectors engineengine">data detectors engineengine</category>
      <category domain="http://securityratty.com/tag/bugs">bugs</category>
      <category domain="http://securityratty.com/tag/microsoft office file">microsoft office file</category>
      <category domain="http://securityratty.com/tag/elevation bug">elevation bug</category>
      <source url="http://feeds.ziffdavisenterprise.com/~r/RSS/cheap_hack/~3/352198240/apple_finally_patches_dns_bug.html">Apple Finally Patches DNS Bug</source>
    </item>
    <item>
      <title><![CDATA[Apple Finally Patches DNS Bug]]></title>
      <link>http://securityratty.com/article/dd4b7bad7cc598605249c8e7e27d4031</link>
      <guid>http://securityratty.com/article/dd4b7bad7cc598605249c8e7e27d4031</guid>
      <description><![CDATA[After taking guff in the press for a while for its lack of a patch for the famous recent DNS bug, Apple has finally issued a patch. The update it comes in also patches 16 other vulnerabilities
Open...]]></description>
      <content:encoded><![CDATA[<a href="http://db.tidbits.com/article/9706">After taking guff in the press for a while</a> for its lack of a patch for the famous recent DNS bug, Apple has finally issued a patch. <a href="http://support.apple.com/kb/HT2647">The update it comes in also patches 16 other vulnerabilities:</a>

<ul>
	<li>Open Scripting Architecture&#151;Privilege elevation bug when loading plug-ins.</li>
	<li>CarbonCore&#151;A stack overflow in handling long file names. Potential code execution.</li>
	<li>CoreGraphics&#151;Two bugs, both code execution, one for malicious graphics, the other for malicious PDFs.</li>
	<li>Data Detectors Engine&#151;Engine may crash when parsing maliciously crafted content.</li>
	<li>Disk Utility&#151;A local user may obtain System privileges.</li>
	<li>OpenLDAP&#151;An ASN parsing bug can lead to a crash.</li>
	<li>OpenSSL&#151;A range checking error from last September (Red Hat patched it in two weeks) can lead to remote code execution.</li>
	<li>PHP&#151;Five different bugs, the worst of which can lead to remote code execution. </li>
	<li>QuickLook&#151;A maliciously crafted Microsoft Office file can cause QuickLooks to crash or allow remote code execution.</li>
	<li>rsync&#151;Path validation errors, which were also reported in 2007, are resolved.</li>
</ul><img src="http://feedproxy.google.com/~r/RSS/cheap_hack/~4/gi6Qi_HP0Y8" height="1" width="1"/>]]></content:encoded>
      <pubDate>Thu, 31 Jul 2008 19:12:34 +0000</pubDate>
      <category domain="http://securityratty.com/tag/code execution">code execution</category>
      <category domain="http://securityratty.com/tag/remote code execution">remote code execution</category>
      <category domain="http://securityratty.com/tag/bug">bug</category>
      <category domain="http://securityratty.com/tag/potential code execution">potential code execution</category>
      <category domain="http://securityratty.com/tag/quicklooka maliciously">quicklooka maliciously</category>
      <category domain="http://securityratty.com/tag/lead">lead</category>
      <category domain="http://securityratty.com/tag/data detectors engineengine">data detectors engineengine</category>
      <category domain="http://securityratty.com/tag/coregraphicstwo bugs">coregraphicstwo bugs</category>
      <category domain="http://securityratty.com/tag/bugs">bugs</category>
      <source url="http://feeds.ziffdavisenterprise.com/~r/RSS/cheap_hack/~3/gi6Qi_HP0Y8/apple_finally_patches_dns_bug.html">Apple Finally Patches DNS Bug</source>
    </item>
    <item>
      <title><![CDATA[RIM fixes critical BlackBerry Enterprise Server bug]]></title>
      <link>http://securityratty.com/article/bfc871ac37ef3d48c54598e291c7f14f</link>
      <guid>http://securityratty.com/article/bfc871ac37ef3d48c54598e291c7f14f</guid>
      <description><![CDATA[Research In Motion patched a critical bug in its BlackBerry Enterprise Server to stymie hackers trying to break into company networks by tricking users of the smart phone into opening rigged...]]></description>
      <content:encoded><![CDATA[Research In Motion patched a critical bug in its BlackBerry Enterprise Server to stymie hackers trying to break into company networks by tricking users of the smart phone into opening rigged PDFs.
<p><a href="http://feeds.computerworld.com/~a/Computerworld/Security/News?a=qmRMdE"><img src="http://feeds.computerworld.com/~a/Computerworld/Security/News?i=qmRMdE" border="0"></img></a></p><img src="http://feeds.computerworld.com/~r/Computerworld/Security/News/~4/339214709" height="1" width="1"/>]]></content:encoded>
      <pubDate>Fri, 18 Jul 2008 09:00:00 +0000</pubDate>
      <category domain="http://securityratty.com/tag/blackberry enterprise server">blackberry enterprise server</category>
      <category domain="http://securityratty.com/tag/company networks">company networks</category>
      <category domain="http://securityratty.com/tag/critical bug">critical bug</category>
      <category domain="http://securityratty.com/tag/smart phone">smart phone</category>
      <category domain="http://securityratty.com/tag/stymie hackers">stymie hackers</category>
      <category domain="http://securityratty.com/tag/research">research</category>
      <category domain="http://securityratty.com/tag/users">users</category>
      <category domain="http://securityratty.com/tag/pdfs">pdfs</category>
      <category domain="http://securityratty.com/tag/motion">motion</category>
      <source url="http://feeds.computerworld.com/~r/Computerworld/Security/News/~3/339214709/article.do">RIM fixes critical BlackBerry Enterprise Server bug</source>
    </item>
    <item>
      <title><![CDATA[Fax Signatures]]></title>
      <link>http://securityratty.com/article/02253ed921c243d2881b5f9b92f99712</link>
      <guid>http://securityratty.com/article/02253ed921c243d2881b5f9b92f99712</guid>
      <description><![CDATA[Aren't fax signatures the weirdest thing? It's trivial to cut and paste -- with real scissors and glue -- anyone's signature onto a document so that it'll look real when faxed. There is so little...]]></description>
      <content:encoded><![CDATA[<p>Aren't fax signatures the weirdest thing? It's trivial to cut and paste -- with real scissors and glue -- anyone's signature onto a document so that it'll look real when faxed.  There is so little security in fax signatures that it's mind-boggling that anyone accepts them.</p>

<p>Yet people do, all the time. I've signed book contracts, credit card authorizations, nondisclosure agreements and all sorts of financial documents -- all by fax. I even have a scanned file of my signature on my computer, so I can virtually cut and paste it into documents and fax them directly from my computer without ever having to print them out.  What in the world is going on here?</p>

<p>And, more importantly, why are fax signatures still being used after years of experience?  Why aren't there many stories of signatures forged through the use of fax machines?</p>

<p>The answer comes from looking at fax signatures not as an isolated security measure, but in the context of the larger system. Fax signatures work because signed faxes exist within a broader communications context.</p>

<p>In a 2003 paper, <a href="http://www.dtc.umn.edu/~odlyzko/doc/econ.psych.security.pdf">"Economics, Psychology, and Sociology of Security,"</a> Professor Andrew Odlyzko looks at fax signatures and concludes:</p>

<blockquote>Although fax signatures have become widespread, their usage is restricted. They are not used for final contracts of substantial value, such as home purchases. That means that the insecurity of fax communications is not easy to exploit for large gain. Additional protection against abuse of fax insecurity is provided by the context in which faxes are used. There are records of phone calls that carry the faxes, paper trails inside enterprises and so on.  Furthermore, unexpected large financial transfers trigger scrutiny. As a result, successful frauds are not easy to carry out by purely technical means.</blockquote>

<p>He's right. Thinking back, there really aren't ways in which a criminal could use a forged document sent by fax to defraud me. I suppose an unscrupulous consulting client could forge my signature on an non-disclosure agreement and then sue me, but that hardly seems worth the effort. And if my broker received a fax document from me authorizing a money transfer to a Nigerian bank account, he would certainly call me before completing it.</p>

<p>Credit card signatures aren't verified in person, either -- and I can already buy things over the phone with a credit card -- so there are no new risks there, and Visa knows how to monitor transactions for fraud. Lots of companies accept purchase orders via fax, even for large amounts of stuff, but there's a physical audit trail, and the goods are shipped to a physical address -- probably one the seller has shipped to before. Signatures are kind of a business lubricant: mostly, they help move things along smoothly.</p>

<p>Except when they don't.</p>

<p>On October 30, 2004, Tristian Wilson was <a href="http://www.theeveningtimes.com/articles/2004/11/04/news/news5.txt">released</a> from a Memphis jail on the authority of a forged fax message. It wasn't even a particularly good forgery. It wasn't on the standard letterhead of the West Memphis Police Department. The name of the policeman who signed the fax was misspelled. And the time stamp on the top of the fax clearly showed that it was sent from a local McDonald's.</p>

<p>The success of this hack has nothing to do with the fact that it was sent over by fax. It worked because the jail had lousy verification procedures. They didn't notice any discrepancies in the fax. They didn't notice the phone number from which the fax was sent. They didn't call and verify that it was official. The jail was accustomed to getting release orders via fax, and just acted on this one without thinking. Would it have been any different had the forged release form been sent by mail or courier?</p>

<p>Yes, fax signatures always exist in context, but sometimes they are the linchpin within that context. If you can mimic enough of the context, or if those on the receiving end become complacent, you can get away with mischief.</p>

<p>Arguably, this is part of the security process. Signatures themselves are poorly defined.  Sometimes a document is valid even if not signed: A person with both hands in a cast can still buy a house. Sometimes a document is invalid even if signed: The signer might be drunk, or have a gun pointed at his head. Or he might be a minor. Sometimes a valid signature isn't enough; in the United States there is an entire infrastructure of "notary publics" who officially witness signed documents. When I started filing my tax returns electronically, I had to sign a document stating that I wouldn't be signing my income tax documents. And banks don't even bother verifying signatures on checks less than $30,000; it's cheaper to deal with fraud after the fact than prevent it.</p>

<p>Over the course of centuries, business and legal systems have slowly sorted out what types of additional controls are required around signatures, and in which circumstances.</p>

<p>Those same systems will be able to sort out fax signatures, too, but it'll be slow. And that's where there will be potential problems. Already fax is a declining technology. In a few years it'll be largely obsolete, replaced by PDFs sent over e-mail and other forms of electronic documentation. In the past, we've had time to figure out how to deal with new technologies. Now, by the time we institutionalize these measures, the technologies are likely to be obsolete.</p>

<p>What that means is people are likely to treat fax signatures -- or whatever replaces them -- exactly the same way as paper signatures. And sometimes that assumption will get them into trouble.</p>

<p>But it won't cause social havoc. Wilson's story is remarkable mostly because it's so exceptional. And even he was rearrested at his home less than a week later. Fax signatures may be new, but fake signatures have always been a possibility.  Our legal and business systems need to deal with the underlying problem -- false authentication -- rather than focus on the technology of the moment. Systems need to defend themselves against the possibility of fake signatures, regardless of how they arrive.</p>

<p>This essay <a href="http://www.wired.com/politics/security/commentary/securitymatters/2008/05/securitymatters_0529">previously appeared</a> on Wired.com.</p><div class="feedflare">
<a href="http://feeds.feedburner.com/~f/schneier/fulltext?a=AcrMPI"><img src="http://feeds.feedburner.com/~f/schneier/fulltext?i=AcrMPI" border="0"></img></a> <a href="http://feeds.feedburner.com/~f/schneier/fulltext?a=cTPMJI"><img src="http://feeds.feedburner.com/~f/schneier/fulltext?i=cTPMJI" border="0"></img></a>
</div>]]></content:encoded>
      <pubDate>Tue, 03 Jun 2008 03:01:20 +0000</pubDate>
      <category domain="http://securityratty.com/tag/fax">fax</category>
      <category domain="http://securityratty.com/tag/fax signatures">fax signatures</category>
      <category domain="http://securityratty.com/tag/fax communications">fax communications</category>
      <category domain="http://securityratty.com/tag/fax insecurity">fax insecurity</category>
      <category domain="http://securityratty.com/tag/insecurity">insecurity</category>
      <category domain="http://securityratty.com/tag/fax machines">fax machines</category>
      <category domain="http://securityratty.com/tag/fax message">fax message</category>
      <category domain="http://securityratty.com/tag/treat fax signatures">treat fax signatures</category>
      <category domain="http://securityratty.com/tag/fax document">fax document</category>
      <source url="http://www.schneier.com/blog/archives/2008/06/fax_signatures.html">Fax Signatures</source>
    </item>
    <item>
      <title><![CDATA[Fax Signatures]]></title>
      <link>http://securityratty.com/article/7f8f07462740c577743663da07c14ae3</link>
      <guid>http://securityratty.com/article/7f8f07462740c577743663da07c14ae3</guid>
      <description><![CDATA[Aren't fax signatures the weirdest thing? It's trivial to cut and paste -- with real scissors and glue -- anyone's signature onto a document so that it'll look real when faxed. There is so little...]]></description>
      <content:encoded><![CDATA[<p>Aren't fax signatures the weirdest thing? It's trivial to cut and paste -- with real scissors and glue -- anyone's signature onto a document so that it'll look real when faxed.  There is so little security in fax signatures that it's mind-boggling that anyone accepts them.</p>

<p>Yet people do, all the time. I've signed book contracts, credit card authorizations, nondisclosure agreements and all sorts of financial documents -- all by fax. I even have a scanned file of my signature on my computer, so I can virtually cut and paste it into documents and fax them directly from my computer without ever having to print them out.  What in the world is going on here?</p>

<p>And, more importantly, why are fax signatures still being used after years of experience?  Why aren't there many stories of signatures forged through the use of fax machines?</p>

<p>The answer comes from looking at fax signatures not as an isolated security measure, but in the context of the larger system. Fax signatures work because signed faxes exist within a broader communications context.</p>

<p>In a 2003 paper, <a href="http://www.dtc.umn.edu/~odlyzko/doc/econ.psych.security.pdf">"Economics, Psychology, and Sociology of Security,"</a> Professor Andrew Odlyzko looks at fax signatures and concludes:</p>

<blockquote>Although fax signatures have become widespread, their usage is restricted. They are not used for final contracts of substantial value, such as home purchases. That means that the insecurity of fax communications is not easy to exploit for large gain. Additional protection against abuse of fax insecurity is provided by the context in which faxes are used. There are records of phone calls that carry the faxes, paper trails inside enterprises and so on.  Furthermore, unexpected large financial transfers trigger scrutiny. As a result, successful frauds are not easy to carry out by purely technical means.</blockquote>

<p>He's right. Thinking back, there really aren't ways in which a criminal could use a forged document sent by fax to defraud me. I suppose an unscrupulous consulting client could forge my signature on an non-disclosure agreement and then sue me, but that hardly seems worth the effort. And if my broker received a fax document from me authorizing a money transfer to a Nigerian bank account, he would certainly call me before completing it.</p>

<p>Credit card signatures aren't verified in person, either -- and I can already buy things over the phone with a credit card -- so there are no new risks there, and Visa knows how to monitor transactions for fraud. Lots of companies accept purchase orders via fax, even for large amounts of stuff, but there's a physical audit trail, and the goods are shipped to a physical address -- probably one the seller has shipped to before. Signatures are kind of a business lubricant: mostly, they help move things along smoothly.</p>

<p>Except when they don't.</p>

<p>On October 30, 2004, Tristian Wilson was <a href="http://www.theeveningtimes.com/articles/2004/11/04/news/news5.txt">released</a> from a Memphis jail on the authority of a forged fax message. It wasn't even a particularly good forgery. It wasn't on the standard letterhead of the West Memphis Police Department. The name of the policeman who signed the fax was misspelled. And the time stamp on the top of the fax clearly showed that it was sent from a local McDonald's.</p>

<p>The success of this hack has nothing to do with the fact that it was sent over by fax. It worked because the jail had lousy verification procedures. They didn't notice any discrepancies in the fax. They didn't notice the phone number from which the fax was sent. They didn't call and verify that it was official. The jail was accustomed to getting release orders via fax, and just acted on this one without thinking. Would it have been any different had the forged release form been sent by mail or courier?</p>

<p>Yes, fax signatures always exist in context, but sometimes they are the linchpin within that context. If you can mimic enough of the context, or if those on the receiving end become complacent, you can get away with mischief.</p>

<p>Arguably, this is part of the security process. Signatures themselves are poorly defined.  Sometimes a document is valid even if not signed: A person with both hands in a cast can still buy a house. Sometimes a document is invalid even if signed: The signer might be drunk, or have a gun pointed at his head. Or he might be a minor. Sometimes a valid signature isn't enough; in the United States there is an entire infrastructure of "notary publics" who officially witness signed documents. When I started filing my tax returns electronically, I had to sign a document stating that I wouldn't be signing my income tax documents. And banks don't even bother verifying signatures on checks less than $30,000; it's cheaper to deal with fraud after the fact than prevent it.</p>

<p>Over the course of centuries, business and legal systems have slowly sorted out what types of additional controls are required around signatures, and in which circumstances.</p>

<p>Those same systems will be able to sort out fax signatures, too, but it'll be slow. And that's where there will be potential problems. Already fax is a declining technology. In a few years it'll be largely obsolete, replaced by PDFs sent over e-mail and other forms of electronic documentation. In the past, we've had time to figure out how to deal with new technologies. Now, by the time we institutionalize these measures, the technologies are likely to be obsolete.</p>

<p>What that means is people are likely to treat fax signatures -- or whatever replaces them -- exactly the same way as paper signatures. And sometimes that assumption will get them into trouble.</p>

<p>But it won't cause social havoc. Wilson's story is remarkable mostly because it's so exceptional. And even he was rearrested at his home less than a week later. Fax signatures may be new, but fake signatures have always been a possibility.  Our legal and business systems need to deal with the underlying problem -- false authentication -- rather than focus on the technology of the moment. Systems need to defend themselves against the possibility of fake signatures, regardless of how they arrive.</p>

<p>This essay <a href="http://www.wired.com/politics/security/commentary/securitymatters/2008/05/securitymatters_0529">previously appeared</a> on Wired.com.</p>

<p>EDITED TO ADD (6/3): 2005 story, "<a href="http://www.law.com/jsp/article.jsp?id=1124960718229">Federal Jury Convicts N.Y. Attorney of Faking Judge's Order</a>."</p><div class="feedflare">
<a href="http://feeds.feedburner.com/~f/schneier/fulltext?a=Cp1KKI"><img src="http://feeds.feedburner.com/~f/schneier/fulltext?i=Cp1KKI" border="0"></img></a> <a href="http://feeds.feedburner.com/~f/schneier/fulltext?a=vxhJ2I"><img src="http://feeds.feedburner.com/~f/schneier/fulltext?i=vxhJ2I" border="0"></img></a>
</div>]]></content:encoded>
      <pubDate>Tue, 03 Jun 2008 03:01:20 +0000</pubDate>
      <category domain="http://securityratty.com/tag/fax">fax</category>
      <category domain="http://securityratty.com/tag/fax signatures">fax signatures</category>
      <category domain="http://securityratty.com/tag/fax communications">fax communications</category>
      <category domain="http://securityratty.com/tag/fax insecurity">fax insecurity</category>
      <category domain="http://securityratty.com/tag/insecurity">insecurity</category>
      <category domain="http://securityratty.com/tag/fax machines">fax machines</category>
      <category domain="http://securityratty.com/tag/fax message">fax message</category>
      <category domain="http://securityratty.com/tag/treat fax signatures">treat fax signatures</category>
      <category domain="http://securityratty.com/tag/fax document">fax document</category>
      <source url="http://www.schneier.com/blog/archives/2008/06/fax_signatures_1.html">Fax Signatures</source>
    </item>
    <item>
      <title><![CDATA[Why Do We Accept Signatures by Fax?]]></title>
      <link>http://securityratty.com/article/ec46457fe9307589ce91fe4fedfce2af</link>
      <guid>http://securityratty.com/article/ec46457fe9307589ce91fe4fedfce2af</guid>
      <description><![CDATA[Aren't fax signatures the weirdest thing? It's trivial to cut and paste -- with real scissors and glue -- anyone's signature onto a document so that it'll look real when faxed. There is so little...]]></description>
      <content:encoded><![CDATA[<p>Aren't fax signatures the weirdest thing? It's trivial to cut and paste -- with real scissors and glue -- anyone's signature onto a document so that it'll look real when faxed.  There is so little security in fax signatures that it's mind-boggling that anyone accepts them. 
</p>

<p>
Yet people do, all the time. I've signed book contracts, credit card authorizations, nondisclosure agreements and all sorts of financial documents -- all by fax. I even have a scanned file of my signature on my computer, so I can virtually cut and paste it into documents and fax them directly from my computer without ever having to print them out.  What in the world is going on here?
</p>

<p>
And, more importantly, why are fax signatures still being used after years of experience?  Why aren't there many stories of signatures forged through the use of fax machines?
</p>

<p>
The answer comes from looking at fax signatures not as an isolated security measure, but in the context of the larger system. Fax signatures work because signed faxes exist within a broader communications context.
</p>

<p>
In a 2003 paper, <cite><a href="http://www.dtc.umn.edu/~odlyzko/doc/econ.psych.security.pdf">Economics, Psychology, and Sociology of Security</a></cite>, professor Andrew Odlyzko looks at fax signatures and concludes:
</p>

<div class="blockquote">
Although fax signatures have become widespread, their usage is restricted. They are not used for final contracts of substantial value, such as home purchases. That means that the insecurity of fax communications is not easy to exploit for large gain. Additional protection against abuse of fax insecurity is provided by the context in which faxes are used. There are records of phone calls that carry the faxes, paper trails inside enterprises and so on.  Furthermore, unexpected large financial transfers trigger scrutiny. As a result, successful frauds are not easy to carry out by purely technical means.
</div> 
<p>
<p>
He's right. Thinking back, there really aren't ways in which a criminal could use a forged document sent by fax to defraud me. I suppose an unscrupulous consulting client could forge my signature on an non-disclosure agreement and then sue me, but that hardly seems worth the effort. And if my broker received a fax document from me authorizing a money transfer to a Nigerian bank account, he would certainly call me before completing it. 
</p>

<p>
Credit card signatures aren't verified in person, either -- and I can already buy things over the phone with a credit card -- so there are no new risks there, and Visa knows how to monitor transactions for fraud. Lots of companies accept purchase orders via fax, even for large amounts of stuff, but there's a physical audit trail, and the goods are shipped to a physical address -- probably one the seller has shipped to before. Signatures are kind of a business lubricant: mostly, they help move things along smoothly.
</p>
<p>
Except when they don't.
</p>
<p>
On October 30, 2004, Tristian Wilson was <a href="http://www.theeveningtimes.com/articles/2004/11/04/news/news5.txt">released</a> from a Memphis jail on the authority of a forged fax message. It wasn't even a particularly good forgery. It wasn't on the standard letterhead of the West Memphis Police Department. The name of the policeman who signed the fax was misspelled. And the time stamp on the top of the fax clearly showed that it was sent from a local McDonald's.
</p>

<p>
The success of this hack has nothing to do with the fact that it was sent over by fax. It worked because the jail had lousy verification procedures. They didn't notice any discrepancies in the fax. They didn't notice the phone number from which the fax was sent. They didn't call and verify that it was official. The jail was accustomed to getting release orders via fax, and just acted on this one without thinking. Would it have been any different had the forged release form been sent by mail or courier?
</p>
<!--pagebreak-->
<p>
Yes, fax signatures always exist in context, but sometimes they are the linchpin within that context. If you can mimic enough of the context, or if those on the receiving end become complacent, you can get away with mischief.
</p>
<p>
Arguably, this is part of the security process. Signatures themselves are poorly defined.  Sometimes a document is valid even if not signed: A person with both hands in a cast can still buy a house. Sometimes a document is invalid even if signed: The signer might be drunk, or have a gun pointed at his head. Or he might be a minor. Sometimes a valid signature isn't enough; in the United States there is an entire infrastructure of "notary publics" who officially witness signed documents. When I started filing my tax returns electronically, I had to sign a document stating that I wouldn't be signing my income tax documents. And banks don't even bother verifying signatures on checks less than $30,000; it's cheaper to deal with fraud after the fact than prevent it.
</p>

<p>
Over the course of centuries, business and legal systems have slowly sorted out what types of additional controls are required around signatures, and in which circumstances.
</p>

<p>
Those same systems will be able to sort out fax signatures, too, but it'll be slow. And that's where there will be potential problems. Already fax is a declining technology. In a few years it'll be largely obsolete, replaced by PDFs sent over e-mail and other forms of electronic documentation. In the past, we've had time to figure out how to deal with new technologies. Now, by the time we institutionalize these measures, the technologies are likely to be obsolete.
</p>
<p>
What that means is people are likely to treat fax signatures -- or whatever replaces them -- exactly the same way as paper signatures. And sometimes that assumption will get them into trouble.
</p>
<p>
But it won't cause social havoc. Wilson's story is remarkable mostly because it's so exceptional. And even he was rearrested at his home less than a week later. Fax signatures may be new, but fake signatures have always been a possibility.  Our legal and business systems need to deal with the underlying problem -- false authentication -- rather than focus on the technology of the moment. Systems need to defend themselves against the possibility of fake signatures, regardless of how they arrive.
</p>
<p>
---
</p>
<p><cite>Bruce Schneier is Chief Security Technology Officer of BT, and author of </cite>Beyond Fear: Thinking Sensibly About Security in an Uncertain World<cite>.</cite>
</p><br style="clear: both;"/>
      <a href="http://www.pheedo.com/click.phdo?s=7ab87f90e62b86d6fc020a727bf5fac9"><img alt="" style="border: 0;" border="0" src="http://www.pheedo.com/img.phdo?s=7ab87f90e62b86d6fc020a727bf5fac9"/></a>
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<a href="http://feeds.feedburner.com/~f/wired/politics/privacy?a=RZ3SLH"><img src="http://feeds.feedburner.com/~f/wired/politics/privacy?i=RZ3SLH" border="0"></img></a> <a href="http://feeds.feedburner.com/~f/wired/politics/privacy?a=kVmJ6h"><img src="http://feeds.feedburner.com/~f/wired/politics/privacy?i=kVmJ6h" border="0"></img></a> <a href="http://feeds.feedburner.com/~f/wired/politics/privacy?a=u6RKCh"><img src="http://feeds.feedburner.com/~f/wired/politics/privacy?i=u6RKCh" border="0"></img></a> <a href="http://feeds.feedburner.com/~f/wired/politics/privacy?a=ZotVrH"><img src="http://feeds.feedburner.com/~f/wired/politics/privacy?i=ZotVrH" border="0"></img></a>
 <a href="http://feeds.wired.com/~f/wired/politics/security?a=eaNyrH"><img src="http://feeds.wired.com/~f/wired/politics/security?i=eaNyrH" border="0"></img></a> <a href="http://feeds.wired.com/~f/wired/politics/security?a=tf8uVh"><img src="http://feeds.wired.com/~f/wired/politics/security?i=tf8uVh" border="0"></img></a> <a href="http://feeds.wired.com/~f/wired/politics/security?a=QWxnGh"><img src="http://feeds.wired.com/~f/wired/politics/security?i=QWxnGh" border="0"></img></a> <a href="http://feeds.wired.com/~f/wired/politics/security?a=MqAv8H"><img src="http://feeds.wired.com/~f/wired/politics/security?i=MqAv8H" border="0"></img></a> </div><img src="http://feeds.feedburner.com/~r/wired/politics/privacy/~4/300217736" height="1" width="1"/><img src="http://feeds.wired.com/~r/wired/politics/security/~4/300217738" height="1" width="1"/>]]></content:encoded>
      <pubDate>Wed, 28 May 2008 21:00:00 +0000</pubDate>
      <category domain="http://securityratty.com/tag/fax">fax</category>
      <category domain="http://securityratty.com/tag/fax communications">fax communications</category>
      <category domain="http://securityratty.com/tag/fax insecurity">fax insecurity</category>
      <category domain="http://securityratty.com/tag/insecurity">insecurity</category>
      <category domain="http://securityratty.com/tag/fax machines">fax machines</category>
      <category domain="http://securityratty.com/tag/fax message">fax message</category>
      <category domain="http://securityratty.com/tag/treat fax signatures">treat fax signatures</category>
      <category domain="http://securityratty.com/tag/fax document">fax document</category>
      <category domain="http://securityratty.com/tag/document">document</category>
      <source url="http://feeds.wired.com/~r/wired/politics/security/~3/300217738/securitymatters_0529">Why Do We Accept Signatures by Fax?</source>
    </item>
    <item>
      <title><![CDATA[Thalys Hits Glitch in Impressive Train Launch]]></title>
      <link>http://securityratty.com/article/017e06ae2b23fbae6f8c43e35598b70e</link>
      <guid>http://securityratty.com/article/017e06ae2b23fbae6f8c43e35598b70e</guid>
      <description><![CDATA[Thalys has launched Internet service on high-speed train routes between Paris, Brussels, Amsterdam, and Cologne: The service hit glitches in its big press rollout, but glitches shouldn't be mistaken...]]></description>
      <content:encoded><![CDATA[<p><img src="http://wifinetnews.com/images/train.jpg" align="right" border="0" hspace="5" /><a href="http://news.yahoo.com/s/pcworld/20080514/tc_pcworld/145901"><strong>Thalys has launched Internet service on high-speed train routes between  Paris, Brussels, Amsterdam, and Cologne:</strong></a> The service hit glitches in its big press rollout, but glitches shouldn't be mistaken for actual performance. The satellite-backed service pulls down 2 Mbps of ruinously expensive backhaul, compressed to provide speeds that feel like 4 Mbps. (Read: faster for email, TIFF images, certain PowerPoint presentations, and Web pages with gzip disabled; normal rate for JPEGs, GIFs, compressed Web pages, and PDFs.)</p>

<p>The service will cost first-class passengers not a thing, but coach will pay &euro;6.50 (US$10) per hour or &euro;13 (US$20) for an entire trip. The train operator is initially equipping 7 trains, but will complete work on all 26 trains by October. Trip durations run from 1 hour 20 minutes to 3 hours.</p>

<p>Most impressively, the consortium that built the system is using a pretty modest antenna that moves automatically to stay in contact with the satellite. It's 80 by 72 cm (31.5 by 28.3 inches), and plans are to shrink that to something 2/3rds the height when a new dish is certified. Ultimately, IDG News Service reports, the group plans to use 3 cm (1 in) high phased-array antennas that would cover the train's roof. Very, very clever, as it jettisons any moving parts.</p>

<p>Three companies worked on the technology: Telenet, handling the billing and authentication, is a Belgian ISP that also runs hotspots; Nokia Siemens is a well-known systems integrator, and is providing some gear and handling installation and integration; 21Net, perhaps the least-well known partner, has the satellite technology. </p>

<p>This project dates back to at least 25-April-2005, a point at which 21Net and Nokia Siemens announced a successful test on the Thalys run from Brussels to Paris. </p>]]></content:encoded>
      <pubDate>Wed, 14 May 2008 11:50:22 +0000</pubDate>
      <category domain="http://securityratty.com/tag/train">train</category>
      <category domain="http://securityratty.com/tag/service hit glitches">service hit glitches</category>
      <category domain="http://securityratty.com/tag/glitches">glitches</category>
      <category domain="http://securityratty.com/tag/service">service</category>
      <category domain="http://securityratty.com/tag/service pulls">service pulls</category>
      <category domain="http://securityratty.com/tag/train operator">train operator</category>
      <category domain="http://securityratty.com/tag/satellite">satellite</category>
      <category domain="http://securityratty.com/tag/satellite technology">satellite technology</category>
      <category domain="http://securityratty.com/tag/nokia siemens">nokia siemens</category>
      <source url="http://wifinetnews.com/archives/008320.html">Thalys Hits Glitch in Impressive Train Launch</source>
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