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Improper Link Resolution Before File Access ('Link Following')

CVE-2019-12571

High
7.1/10

Summary

A vulnerability in the London Trust Media Private Internet Access (PIA) VPN Client v0.9.8 beta (build 02099) for macOS could allow an authenticated, local attacker to overwrite arbitrary files. When the client initiates a connection, the XML /tmp/pia-watcher.plist file is created. If the file exists, it will be truncated and the contents completely overwritten. This file is removed on disconnect. An unprivileged user can create a hard or soft link to arbitrary files owned by any user on the system, including root. This creates a denial of service condition and possible data loss if leveraged by a malicious local user.

  • LOW
  • LOCAL
  • HIGH
  • UNCHANGED
  • NONE
  • LOW
  • NONE
  • HIGH

CWE-59 - Improper Link Resolution Before File Access

'Improper link resolution before file access' occurs when software accesses a file resource but fails to verify that the file isn't a link or shortcut to another file. An attacker can potentially gain access to arbitrary files and from there the impact can vary, depending on the application, from sensitive data exposure to remote code execution.

References

Advisory Timeline

  • Published