glsa-201512-03.xml


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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd">
<glsa id="201512-03">
  <title>GRUB: Authentication bypass</title>
  <synopsis>GRUB's authentication prompt can be bypassed by entering a sequence
    of backspace characters.
  </synopsis>
  <product type="ebuild">grub</product>
  <announced>2015-12-19</announced>
  <revised count="1">2015-12-19</revised>
  <bug>568326</bug>
  <access>local</access>
  <affected>
    <package name="sys-boot/grub" auto="no" arch="*">
      <unaffected range="ge">2.02_beta2-r8</unaffected>
      <unaffected range="rge">0.97</unaffected>
      <vulnerable range="lt">2.02_beta2-r8</vulnerable>
    </package>
  </affected>
  <background>
    <p>GNU GRUB is a multiboot boot loader used by most Linux systems.</p>
  </background>
  <description>
    <p>An integer underflow in GRUB’s username/password authentication code
      has been discovered.
    </p>
  </description>
  <impact type="normal">
    <p>An attacker with access to the system console may bypass the username
      prompt by entering a sequence of backspace characters, allowing them e.g.
      to get full access to GRUB’s console or to load a customized kernel.
    </p>
  </impact>
  <workaround>
    <p>There is no known workaround at this time.</p>
  </workaround>
  <resolution>
    <p>All GRUB 2.x users should upgrade to the latest version:</p>
    
    <code>
      # emerge --sync
      # emerge --ask --oneshot --verbose "&gt;=sys-boot/grub-2.02_beta2-r8"
    </code>
    
    <p>After upgrading, make sure to run the grub2-install command with options
      appropriate for your system. See the GRUB2 Quick Start guide in the
      references below for examples. Your system will be vulnerable until this
      action is performed.
    </p>
  </resolution>
  <references>
    <uri link="https://nvd.nist.gov/nvd.cfm?cvename=CVE-2015-8370">CVE-2015-8370</uri>
    <uri link="https://wiki.gentoo.org/wiki/GRUB2_Quick_Start">GRUB2 Quick
      Start guide
    </uri>
  </references>
  <metadata tag="requester" timestamp="2015-12-19T13:09:44Z">
    keytoaster
  </metadata>
  <metadata tag="submitter" timestamp="2015-12-19T14:20:07Z">
    keytoaster
  </metadata>
</glsa>