CVE-2023-45813

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.

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.

Summary

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..

Details

https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13

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.

PoC

I have uploaded a secret gist containing a PoC (https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c). By adding one special character at the end of the user argument of the URL, the regular expression will take exponentially longer to compute.

For a string of size 10k, the regex will take 0.01s without the well-crafted URL and 1.3s with the well-crafted URL exploit. For a string of size 50k, the regex will take 0.03s without the well-crafted URL and 35s with the well-crafted URL exploit. For a string of size 100k, the regex will take 0.05s without the well-crafted URL and over 200s with the well-crafted URL exploit.

The regular expression used in the validators library versions [0.20, 0.11] is vulnerable to this attack. Version 0.21 appears to be unaffected, but it no longer contains a single regular expression.

Impact

An attacker could exploit this vulnerability to cause a denial of service or increased resource usage.

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.

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.

Summary

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..

Details

https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13

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.

PoC

I have uploaded a secret gist containing a PoC (https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c). By adding one special character at the end of the user argument of the URL, the regular expression will take exponentially longer to compute.

For a string of size 10k, the regex will take 0.01s without the well-crafted URL and 1.3s with the well-crafted URL exploit. For a string of size 50k, the regex will take 0.03s without the well-crafted URL and 35s with the well-crafted URL exploit. For a string of size 100k, the regex will take 0.05s without the well-crafted URL and over 200s with the well-crafted URL exploit.

The regular expression used in the validators library versions [0.20, 0.11] is vulnerable to this attack. Version 0.21 appears to be unaffected, but it no longer contains a single regular expression.

Impact

An attacker could exploit this vulnerability to cause a denial of service or increased resource usage.

Summary

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..

Details

https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13

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.

PoC

I have uploaded a secret gist containing a PoC (https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c). By adding one special character at the end of the user argument of the URL, the regular expression will take exponentially longer to compute.

For a string of size 10k, the regex will take 0.01s without the well-crafted URL and 1.3s with the well-crafted URL exploit. For a string of size 50k, the regex will take 0.03s without the well-crafted URL and 35s with the well-crafted URL exploit. For a string of size 100k, the regex will take 0.05s without the well-crafted URL and over 200s with the well-crafted URL exploit.

The regular expression used in the validators library versions [0.20, 0.11] is vulnerable to this attack. Version 0.21 appears to be unaffected, but it no longer contains a single regular expression.

Impact

An attacker could exploit this vulnerability to cause a denial of service or increased resource usage.