glsa-201603-04.xml


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<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE glsa SYSTEM "http://www.gentoo.org/dtd/glsa.dtd">
<glsa id="201603-04">
  <title>FUSE: incorrect filtering of environment variables leading to
    privilege escalation
  </title>
  <synopsis>The fusermount binary in FUSE does not properly clear the
    environment before invoking mount or umount as root that allows a local
    user to overwrite arbitrary files.
  </synopsis>
  <product type="ebuild">fuse</product>
  <announced>2016-03-09</announced>
  <revised count="1">2016-03-09</revised>
  <bug>550152</bug>
  <access>local</access>
  <affected>
    <package name="sys-fs/fuse" auto="yes" arch="*">
      <unaffected range="ge">2.9.4</unaffected>
      <vulnerable range="lt">2.9.4</vulnerable>
    </package>
  </affected>
  <background>
    <p>FUSE provides an interface for filesystems implemented in userspace.</p>
  </background>
  <description>
    <p>The fusermount binary calls setuid(geteuid()) to reset the RUID when it
      invokes /bin/mount so that it can use privileged mount options that are
      normally restricted if RUID != EUID.  FUSE does not properly clear
      environment variables before invoking mount or umount as root allowing
      this to be passed to operations using elevated privileges such as
      LIBMOUNT_MTAB that is used by the mount commands debugging feature.
    </p>
  </description>
  <impact type="normal">
    <p>The FUSE vulnerability allows a local, unprivileged user to overwrite
      arbitrary files on the system.
    </p>
  </impact>
  <workaround>
    <p>There is no known work around at this time.</p>
  </workaround>
  <resolution>
    <p>All FUSE users should upgrade to the latest version:</p>
    
    <code>
      # emerge --sync
      # emerge --ask --oneshot --verbose "&gt;=sys-fs/fuse-2.9.4"
    </code>
  </resolution>
  <references>
    <uri link="https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-3202">
      CVE-2015-3202
    </uri>
  </references>
  <metadata tag="requester" timestamp="2015-09-09T05:09:39Z">
    BlueKnight
  </metadata>
  <metadata tag="submitter" timestamp="2016-03-09T17:59:40Z">b-man</metadata>
</glsa>