gnu bash CVE-2019-18276 vulnerability in GNU and Other Products
Published on November 28, 2019

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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.

Vendor Advisory NVD

Vulnerability Analysis

CVE-2019-18276 is exploitable with local system access, and requires small amount of user privileges. This vulnerability is considered to have a low attack complexity. Public availability of a proof of concept (POC) exploit exists for CVE-2019-18276. The potential impact of an exploit of this vulnerability is considered to be very high.

Attack Vector:
LOCAL
Attack Complexity:
LOW
Privileges Required:
LOW
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
HIGH
Integrity Impact:
HIGH
Availability Impact:
HIGH

Weakness Type

Improper Check for Dropped Privileges

The software attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded. If the drop fails, the software will continue to run with the raised privileges, which might provide additional access to unprivileged users.


Products Associated with CVE-2019-18276

You can be notified by email with stack.watch whenever vulnerabilities like CVE-2019-18276 are published in these products:

GNU Bash
 
NetApp Hci Management Node
 
NetApp Oncommand Unified Manager
 
NetApp Solidfire
 
Oracle Communications Cloud Native Core Policy
 

Exploit Probability

EPSS
49.61%
Percentile
97.73%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.