CVE-2019-18276

7.8HIGH

Key Information:

Vendor
Gnu
Status
Bash
Vendor
CVE Published:
28 November 2019

Badges

👾 Exploit Exists🟡 Public PoC

Summary

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.

Exploit Proof of Concept (PoC)

PoC code is written by security researchers to demonstrate the vulnerability can be exploited. PoC code is also a key component for weaponization which could lead to ransomware.

CVE-2019-18276
Created by M-ensimag

References

https://lists.apache.org/thread.html/rf9fa47ab66495c78bb4...
mailing-listx_refsource_MLIST
https://security.gentoo.org/glsa/202105-34
vendor-advisoryx_refsource_GENTOO
https://www.oracle.com/security-alerts/cpuapr2022.html
x_refsource_MISC

CVSS V3.1

Score:
7.8
Severity:
HIGH
Confidentiality:
High
Integrity:
High
Availability:
High
Attack Vector:
Local
Attack Complexity:
Low
Privileges Required:
Low
User Interaction:
None
Scope:
Unchanged

Timeline

  • 🟡

    Public PoC available

  • 👾

    Exploit known to exist

  • Vulnerability published

  • Vulnerability Reserved

.