CVE-2019-19726 Information

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.

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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://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

Attack Complexity

LOW

Privileges Required

LOW

User Interaction Required

LOW

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

HIGH

Base Score

HIGH

Base Severity

7.8