CVE Vulnerabilities

CVE-2019-12577

Incorrect Permission Assignment for Critical Resource

Published: Jul 11, 2019 | Modified: Sep 08, 2021
CVSS 3.x
7.8
HIGH
Source:
NVD
CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS 2.x
7.2 HIGH
AV:L/AC:L/Au:N/C:C/I:C/A:C
RedHat/V2
RedHat/V3
Ubuntu

A vulnerability in the London Trust Media Private Internet Access (PIA) VPN Client v82 for macOS could allow an authenticated, local attacker to run arbitrary code with elevated privileges. The macOS binary openvpn_launcher.64 is setuid root. This binary creates /tmp/pia_upscript.sh when executed. Because the file creation mask (umask) is not reset, the umask value is inherited from the calling process. This value can be manipulated to cause the privileged binary to create files with world writable permissions. A local unprivileged user can modify /tmp/pia_upscript.sh during the connect process to execute arbitrary code as the root user.

Weakness

The product specifies permissions for a security-critical resource in a way that allows that resource to be read or modified by unintended actors.

Affected Software

Name Vendor Start Version End Version
Private_internet_access_vpn_client Londontrustmedia 82 (including) 82 (including)

Potential Mitigations

  • Run the code in a “jail” or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which files can be accessed in a particular directory or which commands can be executed by the software.
  • OS-level examples include the Unix chroot jail, AppArmor, and SELinux. In general, managed code may provide some protection. For example, java.io.FilePermission in the Java SecurityManager allows the software to specify restrictions on file operations.
  • This may not be a feasible solution, and it only limits the impact to the operating system; the rest of the application may still be subject to compromise.
  • Be careful to avoid CWE-243 and other weaknesses related to jails.

References