Access Restriction Bypass Affecting glibc package, versions <2.21-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-GLIBC-356522
- published14 Mar 2016
- disclosed14 Mar 2016
Introduced: 14 Mar 2016
CVE-2016-2856 (opens in a new tab)How to fix?
Upgrade Debian:unstable glibc to version 2.21-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream glibc package and not the glibc package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
pt_chown in the glibc package before 2.19-18+deb8u4 on Debian jessie; the elibc package before 2.15-0ubuntu10.14 on Ubuntu 12.04 LTS and before 2.19-0ubuntu6.8 on Ubuntu 14.04 LTS; and the glibc package before 2.21-0ubuntu4.2 on Ubuntu 15.10 and before 2.23-0ubuntu1 on Ubuntu 16.04 LTS and 16.10 lacks a namespace check associated with file-descriptor passing, which allows local users to capture keystrokes and spoof data, and possibly gain privileges, via pts read and write operations, related to debian/sysdeps/linux.mk. NOTE: this is not considered a vulnerability in the upstream GNU C Library because the upstream documentation has a clear security recommendation against the --enable-pt_chown option.
References
- https://security-tracker.debian.org/tracker/CVE-2016-2856
- http://anonscm.debian.org/cgit/pkg-glibc/glibc.git/commit/?h=jessie&id=09f7764882a81e13e7b5d87d715412283a6ce403
- http://anonscm.debian.org/cgit/pkg-glibc/glibc.git/commit/?h=jessie&id=11475c083282c1582c4dd72eecfcb2b7d308c958
- http://people.canonical.com/~ubuntu-security/cve/2016/CVE-2016-2856.html
- http://www.halfdog.net/Security/2015/PtChownArbitraryPtsAccessViaUserNamespace/
- http://www.openwall.com/lists/oss-security/2016/02/23/3
- http://www.openwall.com/lists/oss-security/2016/03/07/2
- http://www.securityfocus.com/bid/84601
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2016-2856
- http://www.ubuntu.com/usn/USN-2985-1
- http://www.ubuntu.com/usn/USN-2985-2