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CVE-2019-19726

Description

OpenBSD through 6.6 allows local users to escalate to root because a 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. Thus, the attacker is able to execute their own library code as root.

POC

Reference

- 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://packetstormsecurity.com/files/174986/glibc-ld.so-Local-Privilege-Escalation.html

- http://seclists.org/fulldisclosure/2019/Dec/31

- http://seclists.org/fulldisclosure/2023/Oct/11

- http://www.openwall.com/lists/oss-security/2023/10/03/2

- https://seclists.org/bugtraq/2019/Dec/25

- https://www.openwall.com/lists/oss-security/2019/12/11/9

Github

- https://github.com/ARPSyndicate/cvemon

- https://github.com/Blacloud226/sao

- https://github.com/alphaSeclab/sec-daily-2019

- https://github.com/anoaghost/Localroot_Compile

- https://github.com/bcoles/local-exploits

- https://github.com/swignore/linpeas

- https://github.com/vshaliii/DC-1-Vulnhub-Walkthrough