Improper Check for Dropped Privileges The advisory has been revoked - it doesn't affect any version of package bash (opens in a new tab)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
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-UBUNTU2004-BASH-581100
- published28 Nov 2019
- disclosed28 Nov 2019
Introduced: 28 Nov 2019
CVE-2019-18276 (opens in a new tab)Amendment
The Ubuntu security team deemed this advisory irrelevant for Ubuntu:20.04.
NVD Description
Note: Versions mentioned in the description apply only to the upstream bash package and not the bash package as distributed by Ubuntu.
An issue was discovered in disable_priv_mode in shell.c in GNU Bash through 5.0 patch 11. By default, if Bash is run with its effective UID not equal to its real UID, it will drop privileges by setting its effective UID to its real UID. However, it does so incorrectly. On Linux and other systems that support "saved UID" functionality, the saved UID is not dropped. An attacker with command execution in the shell can use "enable -f" for runtime loading of a new builtin, which can be a shared object that calls setuid() and therefore regains privileges. However, binaries running with an effective UID of 0 are unaffected.
References
- http://people.ubuntu.com/~ubuntu-security/cve/CVE-2019-18276
- https://security.netapp.com/advisory/ntap-20200430-0003/
- https://security-tracker.debian.org/tracker/CVE-2019-18276
- https://security.gentoo.org/glsa/202105-34
- https://github.com/bminor/bash/commit/951bdaad7a18cc0dc1036bba86b18b90874d39ff
- http://packetstormsecurity.com/files/155498/Bash-5.0-Patch-11-Privilege-Escalation.html
- https://www.youtube.com/watch?v=-wGtxJ8opa8
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772@%3Cdev.mina.apache.org%3E
- https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4120b0754dd9531ca2ff0430f6685ac9b07772%40%3Cdev.mina.apache.org%3E
- https://www.oracle.com/security-alerts/cpuapr2022.html
- https://www.exploit-db.com/exploits/47726