Arch Linux: ASA-201711-40 High: Shadowsocks-Libev Command Execution

Arch Linux Security Advisory ASA-201711-40
=========================================
Severity: High
Date    : 2017-11-30
CVE-ID  : CVE-2017-15924
Package : shadowsocks-libev
Type    : arbitrary command execution
Remote  : No
Link    : https://security.archlinux.org/AVG-474

Summary
======
The package shadowsocks-libev before version 3.1.1-1 is vulnerable to
arbitrary command execution.

Resolution
=========
Upgrade to 3.1.1-1.

# pacman -Syu "shadowsocks-libev>=3.1.1-1"

The problem has been fixed upstream in version 3.1.1.

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

Description
==========
In manager.c in ss-manager in shadowsocks-libev before 3.1.1, improper
parsing allows command injection via shell metacharacters in a JSON
configuration request received via 127.0.0.1 UDP traffic, related to
the add_server, build_config, and construct_command_line functions.

Impact
=====
A local attacker could send a specially crafted configuration request
to localhost that, when processed by ss-manager, leads to the execution
of arbitrary commands as the user running ss-manager.

References
=========
https://www.openwall.com/lists/oss-security/2017/10/13/2
https://github.com/shadowsocks/shadowsocks-libev/commit/c67d275803dc6ea22c558d06b1f7ba9f94cd8de3
https://github.com/shadowsocks/shadowsocks-libev/issues/1734
https://www.x41-dsec.de/lab/advisories/x41-2017-010-shadowsocks-libev/
https://security.archlinux.org/CVE-2017-15924