CVE-2016-7097
First published: Mon Aug 22 2016(Updated: )
A vulnerability was found in the Linux kernel. When file permissions are modified via chmod and the user is not in the owning group or capable of CAP_FSETID, the setgid bit is cleared in inode_change_ok(). Setting a POSIX ACL via setxattr sets the filepermissions as well as the new ACL, but doesn't clear the setgid bit in a similar way; this allows to bypass the check in chmod. Suggested upstream patch: <a href="http://marc.info/?l=linux-fsdevel&m=147162313630259&w=2">http://marc.info/?l=linux-fsdevel&m=147162313630259&w=2</a> <a href="http://www.spinics.net/lists/linux-fsdevel/msg101138.html">http://www.spinics.net/lists/linux-fsdevel/msg101138.html</a> Upstream commits: <a href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=073931017b49d9458aa351605b43a7e34598caef">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=073931017b49d9458aa351605b43a7e34598caef</a> <a href="https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31">https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31</a> Previous suggestions: <a href="http://www.spinics.net/lists/linux-fsdevel/msg98328.html">http://www.spinics.net/lists/linux-fsdevel/msg98328.html</a> <a href="https://patchwork.kernel.org/patch/9137067/">https://patchwork.kernel.org/patch/9137067/</a> <a href="https://patchwork.kernel.org/patch/9138935/">https://patchwork.kernel.org/patch/9138935/</a> CVE request+assignment: <a href="http://seclists.org/oss-sec/2016/q3/380">http://seclists.org/oss-sec/2016/q3/380</a> <a href="http://seclists.org/oss-sec/2016/q3/382">http://seclists.org/oss-sec/2016/q3/382</a>
Credit: secalert@redhat.com secalert@redhat.com
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Linux Linux kernel | <=4.8.2 | |
| Google Android | ||
| debian/linux | 5.10.223-1 5.10.226-1 6.1.115-1 6.1.119-1 6.11.10-1 6.12.5-1 |
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Reference Links
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=073931017b49d9458aa351605b43a7e34598caef
- http://marc.info/?l=linux-fsdevel&m=147162313630259&w=2
- http://rhn.redhat.com/errata/RHSA-2017-0817.html
- http://www.openwall.com/lists/oss-security/2016/08/26/3
- http://www.securityfocus.com/bid/92659
- http://www.securitytracker.com/id/1038201
- http://www.spinics.net/lists/linux-fsdevel/msg98328.html
- http://www.ubuntu.com/usn/USN-3146-1
- http://www.ubuntu.com/usn/USN-3146-2
- http://www.ubuntu.com/usn/USN-3147-1
- https://access.redhat.com/errata/RHSA-2017:1842
- https://access.redhat.com/errata/RHSA-2017:2077
- https://access.redhat.com/errata/RHSA-2017:2669
- https://bugzilla.redhat.com/show_bug.cgi?id=1368938
- https://github.com/torvalds/linux/commit/073931017b49d9458aa351605b43a7e34598caef
- https://source.android.com/security/bulletin/2017-04-01
- https://support.f5.com/csp/article/K31603170?utm_source=f5support&%3Butm_medium=RSS
- http://marc.info/?l=linux-fsdevel&m=147162313630259&w=2
- https://support.f5.com/csp/article/K31603170?utm_source=f5support&amp%3Butm_medium=RSS
- https://launchpad.net/bugs/cve/CVE-2016-7097
- http://www.spinics.net/lists/linux-fsdevel/msg101138.html
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=073931017b49d9458aa351605b43a7e34598caef
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=497de07d89c1410d76a15bec2bb41f24a2a89f31
- https://patchwork.kernel.org/patch/9137067/
- https://patchwork.kernel.org/patch/9138935/
- http://seclists.org/oss-sec/2016/q3/380
- http://seclists.org/oss-sec/2016/q3/382
- https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1368939
- https://access.redhat.com/support/policy/updates/errata/
- https://rhn.redhat.com/errata/RHSA-2017-0817.html
- https://source.android.com/docs/security/bulletin/2017-04-01 (Advisory)
- https://git.kernel.org/linus/073931017b49d9458aa351605b43a7e34598caef
- https://security-tracker.debian.org/tracker/CVE-2016-7097
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2016-7097
- https://nvd.nist.gov/vuln/detail/CVE-2016-7097
- https://ubuntu.com/security/CVE-2016-7097
Frequently Asked Questions
What is CVE-2016-7097?
CVE-2016-7097 is a vulnerability in the Linux kernel that allows local users to gain group privileges.
How does CVE-2016-7097 work?
CVE-2016-7097 works by preserving the setgid bit during a setxattr call, which can be leveraged by local users to gain group privileges.
What is the severity of CVE-2016-7097?
CVE-2016-7097 has a severity rating of medium.
Which software versions are affected by CVE-2016-7097?
The software versions affected by CVE-2016-7097 include Linux kernel versions through 4.8.2.
How can I fix CVE-2016-7097?
To fix CVE-2016-7097, update your Linux kernel to a version that is higher than 4.8.2.
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