SB2019041211 - Multiple vulnerabilities in Linux kernel

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Main Vulnerability Database SB2019041211

SB2019041211 - Multiple vulnerabilities in Linux kernel

Published: April 12, 2019 Updated: July 17, 2020

Security Bulletin ID SB2019041211
Severity
Low
Patch available
YES
Number of vulnerabilities 2
Exploitation vector Local access
Highest impact Information disclosure

Breakdown by Severity

Low 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 2 secuirty vulnerabilities.


1) Race condition (CVE-ID: CVE-2019-3901)

The vulnerability allows a local authenticated user to gain access to sensitive information.

A race condition in perf_event_open() allows local attackers to leak sensitive data from setuid programs. As no relevant locks (in particular the cred_guard_mutex) are held during the ptrace_may_access() call, it is possible for the specified target task to perform an execve() syscall with setuid execution before perf_event_alloc() actually attaches to it, allowing an attacker to bypass the ptrace_may_access() check and the perf_event_exit_task(current) call that is performed in install_exec_creds() during privileged execve() calls. This issue affects kernel versions before 4.8.


2) Race condition (CVE-ID: CVE-2019-11190)

The vulnerability allows a local authenticated user to gain access to sensitive information.

The Linux kernel before 4.8 allows local users to bypass ASLR on setuid programs (such as /bin/su) because install_exec_creds() is called too late in load_elf_binary() in fs/binfmt_elf.c, and thus the ptrace_may_access() check has a race condition when reading /proc/pid/stat.


Remediation

Install update from vendor's website.

References