ASA-202004-4 log generated external raw
[ASA-202004-4] linux: privilege escalation |
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Arch Linux Security Advisory ASA-202004-4
=========================================
Severity: High
Date : 2020-04-01
CVE-ID : CVE-2020-8835
Package : linux
Type : privilege escalation
Remote : No
Link : https://security.archlinux.org/AVG-1122
Summary
=======
The package linux before version 5.5.13.arch2-1 is vulnerable to
privilege escalation.
Resolution
==========
Upgrade to 5.5.13.arch2-1.
# pacman -Syu "linux>=5.5.13.arch2-1"
The problem has been fixed upstream in version 5.5.13.arch2.
Workaround
==========
BPF access can be restricted to privileged users by setting
kernel.unprivileged_bpf_disabled to 1:
# sysctl -w kernel.unprivileged_bpf_disabled=1
Description
===========
An out-of-bounds access flaw was found in the Linux kernel’s
implementation of the eBPF code verifier, where an incorrect register
bounds calculation while checking 32-bit instructions in an eBPF
program occurs. This flaw allows an unprivileged user or process to
execute eBPF programs to crash the kernel, resulting in a denial of
service or potentially gaining root privileges on the system.
Impact
======
An unprivileged local user or process can crash the kernel, resulting
in a denial of service, or potentially gain root privileges on the
system.
References
==========
https://www.thezdi.com/blog/2020/3/19/pwn2own-2020-day-one-results
https://lore.kernel.org/bpf/20200330160324.15259-1-daniel@iogearbox.net/T/
https://www.openwall.com/lists/oss-security/2020/03/30/3
https://security.archlinux.org/CVE-2020-8835
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