Arch Linux Security Advisory ASA-201901-4
========================================
Severity: Medium
Date    : 2019-01-08
CVE-ID  : CVE-2018-6954 CVE-2018-16866
Package : systemd
Type    : multiple issues
Remote  : No
Link    : https://security.archlinux.org/AVG-615

Summary
======
The package systemd before version 240.0-3 is vulnerable to multiple
issues including arbitrary file overwrite and information disclosure.

Resolution
=========
Upgrade to 240.0-3.

# pacman -Syu "systemd>=240.0-3"

The problems have been fixed upstream in version 240.0.

Workaround
=========
None.

Description
==========
- CVE-2018-6954 (arbitrary file overwrite)

systemd-tmpfiles in systemd through 237 mishandles symlinks present in
non-terminal path components, which allows local users to obtain
ownership of arbitrary files via vectors involving creation of a
directory and a file under that directory, and later replacing that
directory with a symlink. This occurs even if the fs.protected_symlinks
sysctl is turned on.

- CVE-2018-16866 (information disclosure)

An out-of-bounds read has been found in the journald component of
systemd >= v221 and < v240, in the syslog_parse_identifier() function
in journald-syslog.c. A crafted syslog message whose last character is
':' can trigger this vulnerability to leak information about the
content of the memory.

Impact
=====
A local attacker is able to obtain ownership of arbitrary files or
disclose information using a specially crafted syslog message.

References
=========
https://github.com/systemd/systemd/issues/7986
https://github.com/systemd/systemd/pull/8822
https://www.qualys.com/2019/01/09/system-down/system-down.txt
https://www.openwall.com/lists/oss-security/2019/01/09/3
https://github.com/systemd/systemd/commit/a6aadf4ae0bae185dc4c414d492a4a781c80ffe5
https://github.com/systemd/systemd/commit/8595102d3ddde6d25c282f965573a6de34ab4421
https://security.archlinux.org/CVE-2018-6954
https://security.archlinux.org/CVE-2018-16866