70 lines
2.7 KiB
XML
70 lines
2.7 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd">
|
|
<glsa id="201612-01">
|
|
<title>GnuPG: RNG output is predictable</title>
|
|
<synopsis>Due to a design flaw, the output of GnuPG's Random Number Generator
|
|
(RNG) is predictable.
|
|
</synopsis>
|
|
<product type="ebuild">gnupg</product>
|
|
<announced>2016-12-02</announced>
|
|
<revised count="1">2016-12-02</revised>
|
|
<bug>591536</bug>
|
|
<access>local</access>
|
|
<affected>
|
|
<package name="app-crypt/gnupg" auto="yes" arch="*">
|
|
<unaffected range="ge">1.4.21</unaffected>
|
|
<vulnerable range="lt">1.4.21</vulnerable>
|
|
</package>
|
|
</affected>
|
|
<background>
|
|
<p>The GNU Privacy Guard, GnuPG, is a free replacement for the PGP suite of
|
|
cryptographic software.
|
|
</p>
|
|
</background>
|
|
<description>
|
|
<p>A long standing bug (since 1998) in Libgcrypt (see “GLSA 201610-04”
|
|
below) and GnuPG allows an attacker to predict the output from the
|
|
standard RNG. Please review the “Entropy Loss and Output Predictability
|
|
in the Libgcrypt PRNG” paper below for a deep technical analysis.
|
|
</p>
|
|
</description>
|
|
<impact type="normal">
|
|
<p>An attacker who obtains 580 bytes of the random number from the standard
|
|
RNG can trivially predict the next 20 bytes of output.
|
|
</p>
|
|
|
|
<p>This flaw does not affect the default generation of keys, because
|
|
running gpg for key creation creates at most 2 keys from the pool. For a
|
|
single 4096 bit RSA key, 512 bytes of random are required and thus for
|
|
the second key (encryption subkey), 20 bytes could be predicted from the
|
|
the first key.
|
|
</p>
|
|
|
|
<p>However, the security of an OpenPGP key depends on the primary key
|
|
(which was generated first) and thus the 20 predictable bytes should not
|
|
be a problem. For the default key length of 2048 bit nothing will be
|
|
predictable.
|
|
</p>
|
|
</impact>
|
|
<workaround>
|
|
<p>There is no known workaround at this time.</p>
|
|
</workaround>
|
|
<resolution>
|
|
<p>All GnuPG 1 users should upgrade to the latest version:</p>
|
|
|
|
<code>
|
|
# emerge --sync
|
|
# emerge --ask --oneshot --verbose ">=app-crypt/gnupg-1.4.21"
|
|
</code>
|
|
|
|
</resolution>
|
|
<references>
|
|
<uri link="https://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-6313">CVE-2016-6313</uri>
|
|
<uri link="http://formal.iti.kit.edu/~klebanov/pubs/libgcrypt-cve-2016-6313.pdf">
|
|
Entropy Loss and Output Predictability in the Libgcrypt PRNG
|
|
</uri>
|
|
<uri link="https://security.gentoo.org/glsa/201610-04">GLSA 201610-04</uri>
|
|
</references>
|
|
<metadata tag="requester" timestamp="2016-11-30T18:28:25Z">whissi</metadata>
|
|
<metadata tag="submitter" timestamp="2016-12-02T09:38:37Z">whissi</metadata>
|
|
</glsa>
|