PT-2019-4881 · Gnu+4 · Gnu Bash+4
Published
2019-11-28
·
Updated
2022-06-07
·
CVE-2019-18276
CVSS v3.1
7.8
High
| Vector | AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Name of the Vulnerable Software and Affected Versions
GNU Bash versions 5.0 patch 11 and earlier
Description
An issue was discovered in the disable priv mode function in shell.c. 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.Recommendations
For GNU Bash versions 5.0 patch 11 and earlier, consider disabling the
disable priv mode function until a patch is available. Restrict access to the enable command with the -f option to minimize the risk of exploitation. Avoid using the enable -f command for runtime loading of new builtins until the issue is resolved. At the moment, there is no information about a newer version that contains a fix for this vulnerability.Exploit
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Weakness Enumeration
Related Identifiers
Affected Products
Centos
Gnu Bash
Linuxmint
Red Hat
Ubuntu