Vulnerabilities > CVE-2022-21658 - Time-of-check Time-of-use (TOCTOU) Race Condition vulnerability in multiple products

047910
CVSS 6.3 - MEDIUM
Attack vector
LOCAL
Attack complexity
HIGH
Privileges required
LOW
Confidentiality impact
NONE
Integrity impact
HIGH
Availability impact
HIGH
local
high complexity
rust-lang
fedoraproject
apple
CWE-367
NVD
Published: 2022-01-20
Updated: 2023-11-07

Summary

Rust is a multi-paradigm, general-purpose programming language designed for performance and safety, especially safe concurrency. The Rust Security Response WG was notified that the `std::fs::remove_dir_all` standard library function is vulnerable a race condition enabling symlink following (CWE-363). An attacker could use this security issue to trick a privileged program into deleting files and directories the attacker couldn't otherwise access or delete. Rust 1.0.0 through Rust 1.58.0 is affected by this vulnerability with 1.58.1 containing a patch. Note that the following build targets don't have usable APIs to properly mitigate the attack, and are thus still vulnerable even with a patched toolchain: macOS before version 10.10 (Yosemite) and REDOX. We recommend everyone to update to Rust 1.58.1 as soon as possible, especially people developing programs expected to run in privileged contexts (including system daemons and setuid binaries), as those have the highest risk of being affected by this. Note that adding checks in your codebase before calling remove_dir_all will not mitigate the vulnerability, as they would also be vulnerable to race conditions like remove_dir_all itself. The existing mitigation is working as intended outside of race conditions.

Vulnerable Configurations

Part Description Count
Application
Rust-Lang
78
OS
Fedoraproject
2
OS
Apple
431

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Leveraging Race Conditions via Symbolic Links
    This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to her. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file she will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.
  • Leveraging Time-of-Check and Time-of-Use (TOCTOU) Race Conditions
    This attack targets a race condition occurring between the time of check (state) for a resource and the time of use of a resource. The typical example is the file access. The attacker can leverage a file access race condition by "running the race", meaning that he would modify the resource between the first time the target program accesses the file and the time the target program uses the file. During that period of time, the attacker could do something such as replace the file and cause an escalation of privilege.

Related news

References