Inefficient Regular Expression Complexity in TorBot

Vulnerability Description

Torbot is an open source tor network intelligence tool. In affected versions the `torbot.modules.validators.validate_link function` uses the python-validators URL validation regex. This particular regular expression has an exponential complexity which allows an attacker to cause an application crash using a well-crafted argument. An attacker can use a well-crafted URL argument to exploit the vulnerability in the regular expression and cause a Denial of Service on the system. The validators file has been removed in version 4.0.0. Users are advised to upgrade. There are no known workarounds for this vulnerability.

References

• https://github.com/DedSecInside/TorBot/security/advisories/GHSA-72qw-p7hh-m3ff
• https://github.com/DedSecInside/TorBot/commit/ef6e06bc7785355b1701d5524eb4550441086ac4