SB2019122804 - Privilege escalation in OpenBSD dynamic loader
Published: December 28, 2019
Security Bulletin ID
SB2019122804
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Local access
Highest impact
Code execution
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Permissions, Privileges, and Access Controls (CVE-ID: CVE-2019-19726)
The vulnerability allows a local usre to escalate privileges on the system.
The vulnerability exists due to check for LD_LIBRARY_PATH in setuid programs can be defeated by setting a
very small RLIMIT_DATA resource limit. When executing chpass or passwd
(which are setuid root), _dl_setup_env in ld.so tries to strip
LD_LIBRARY_PATH from the environment, but fails when it cannot allocate
memory. A local user can execute arbitrary code on the system with root privileges.
Remediation
Install update from vendor's website.
References
- http://packetstormsecurity.com/files/155658/Qualys-Security-Advisory-OpenBSD-Dynamic-Loader-Privilege-Escalation.html
- http://packetstormsecurity.com/files/155764/OpenBSD-Dynamic-Loader-chpass-Privilege-Escalation.html
- http://seclists.org/fulldisclosure/2019/Dec/31
- https://seclists.org/bugtraq/2019/Dec/25
- https://www.openbsd.org/errata66.html
- https://www.openwall.com/lists/oss-security/2019/12/11/9
- https://github.com/rapid7/metasploit-framework/tree/master/modules/exploits/openbsd/local/dynamic_loader_chpass_privesc.rb