Improper Check for Dropped Privileges in Bash - CVE-2019-18276

Vulnerability identifier: #VU24690

CSH Severity: Low

CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2019-18276

CWE-ID: CWE-273

Exploitation vector: Local access

Exploit availability: Public exploit is available

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists in "disable_priv_mode()" function in shell.c due to the affected software attempts to drop privileges but does not check or incorrectly checks to see if the drop succeeded. A local user 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.

Bash
DataMosaix Private Cloud
cflinuxfs3
Watson Studio on Cloud Pak for Data
Gentoo Linux
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64
Red Hat Enterprise Linux for Power, little endian
Red Hat Enterprise Linux for IBM z Systems
Ubuntu
Cloud Pak for Security (CP4S)
Oracle Communications Cloud Native Core Policy
Traffix SDC
PowerScale OneFS
Junos cRPD
Web Terminal
Netcool Operations Insight
IBM Cloud Transformation Advisor
Juniper Cloud Native Router
bash (Ubuntu package)
bash (Red Hat package)
IBM Security Verify Access

Cybersecurity Help is currently unaware of any official solution to address this vulnerability.

DataMosaix Private Cloud - update to 7.09
cflinuxfs3 - update to 0.287.0
Cloud Pak for Security (CP4S) - update to 1.8.0.0
PowerScale OneFS - addressed in versions 9.1.0.21, 9.2.1.14, 9.3.0.7, 9.4.0.4
Web Terminal - update to 1.3
Netcool Operations Insight - update to 1.6.8
IBM Cloud Transformation Advisor - update to 3.10.0
bash (Ubuntu package) - addressed in versions 4.4.18-2ubuntu1.3, 5.0-6ubuntu1.2
bash (Red Hat package) - update to 4.4.19-14.el8
Watson Studio on Cloud Pak for Data - addressed in versions 4.8.7, 5.1.0
IBM Security Verify Access - update to 10.0.7.0
Juniper Cloud Native Router - update to 23.4R1
Junos cRPD - update to 23.4R1

• Exploit #5834 - Bash 5.0 Patch 11 - SUID Priv Drop Exploit (June 17, 2021)

• http://packetstormsecurity.com/files/155498/Bash-5.0-Patch-11-Privilege-Escalation.html
• https://github.com/bminor/bash/commit/951bdaad7a18cc0dc1036bba86b18b90874d39ff
• https://www.youtube.com/watch?v=-wGtxJ8opa8

• Privilege escalation in GNU Bash
• Multiple vulnerabilities in F5 Traffix SDC
• Red Hat Enterprise Linux 8 update for bash
• Gentoo update for Bash
• Multiple vulnerabilities in Red Hat Web Terminal
• Ubuntu update for bash
• Cloud Foundry Foundation cflinuxfs3 update for Bash
• Multiple vulnerabilities in Oracle Communications Cloud Native Core Policy
• Multiple vulnerabilities in IBM Cloud Pak for Security
• Multiple vulnerabilities in Dell PowerScale OneFS
• Multiple vulnerabilities in IBM Netcool Operations Insight
• Multiple vulnerabilities in IBM Security Verify Access
• Multiple vulnerabilities in Juniper Cloud Native Router
• Multiple vulnerabilities in Juniper Networks Junos cRPD
• Multiple vulnerabilities in IBM Cloud Transformation Advisor
• Multiple vulnerabilities in Rockwell Automation DataMosaix Private Cloud
• Multiple vulnerabilities in IBM Watson Studio on Cloud Pak for Data