CVE-2023-45813: Torbot TorBot Vulnerable To Inefficient Regular Vulnerability

MODERATE
Advisory Identifier: GHSA-72qw-p7hh-m3ff
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CVSS 4.6
CWE-1333
Published
Advisory Summary

CVE-2023-45813 is a MODERATE (CVSS 4.6) torbot vulnerable to inefficient regular vulnerability (CWE-1333: Inefficient Regular Expression Complexity) affecting Torbot libraries in the PyPI ecosystem. The issue involves torbot vulnerable to inefficient regular expression complexity in validate_link. Remediation is available by upgrading affected packages to version 4.0.0.

CVE-2023-45813 at a Glance

CVE Identifier CVE-2023-45813
GHSA Identifier GHSA-72qw-p7hh-m3ff
Severity MODERATE
CVSS v3.1 Base Score 4.6
CWE Classification CWE-1333: Inefficient Regular Expression Complexity
Affected Product Torbot
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 4.6

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Physical (AV:P)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2023-45813

To remediate this vulnerability, upgrade all affected Torbot dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

torbot fixed: 4.0.0 
pip install torbot>=4.0.0
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

pip show torbot

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2023-45813, inspect your installed packages using pip:

pip show torbot

Analyze the terminal output to locate any version of Torbot in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 4.0.0), your application is affected.

Note: The pip show torbot command checks currently installed packages in your active Python environment.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-1333: Inefficient Regular Expression Complexity, where the product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential. In Torbot, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### 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.

CVE-2023-45813 Affected Torbot Versions

1 component(s)
Fixed Versions:
4.0.0
Product / Package Ecosystem Affected Versions Fixed Version
torbot
pypi/torbot
PyPI
< 4.0.0
4.0.0

References

GitHub Advisory / Wiki ADVISORY
https://github.com/DedSecInside/TorBot/security/advisories/GHSA-72qw-p7hh-m3ff
NVD — CVE-2023-45813 NVD
https://nvd.nist.gov/vuln/detail/CVE-2023-45813
Security Fix Commit FIX COMMIT
https://github.com/DedSecInside/TorBot/commit/ef6e06bc7785355b1701d5524eb4550441086ac4
Torbot Source Repository REPOSITORY
https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c
Torbot Source Repository REPOSITORY
https://github.com/DedSecInside/TorBot
Torbot Source Repository REPOSITORY
https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13

Frequently Asked Questions

What is CVE-2023-45813?
CVE-2023-45813 is a security vulnerability in Torbot involving TorBot vulnerable to Inefficient Regular Expression Complexity in validate_link under CWE-1333: Inefficient Regular Expression Complexity.
Which Torbot versions are affected?
Affected versions include releases prior to 4.0.0 across affected packages: torbot.
What version fixes CVE-2023-45813?
Upgrading to 4.0.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is torbot affected?
Yes, torbot is affected in releases prior to 4.0.0. Upgrade your dependency to 4.0.0 or later.
What is the CVSS score of CVE-2023-45813?
CVE-2023-45813 has a CVSS v3.1 base score of 4.6 (MODERATE) with vector string CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2023-45813?
CVE-2023-45813 is classified under CWE-1333: Inefficient Regular Expression Complexity (The product uses a regular expression with a worst-case computational complexity that is inefficient and possibly exponential.).
How can I check PyPI dependencies for CVE-2023-45813?
Run the dependency tree command: 'pip show torbot'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-72qw-p7hh-m3ff",
  "modified" : "2023-10-19T12:33:03Z",
  "published" : "2023-10-19T12:33:03Z",
  "aliases" : [ "CVE-2023-45813" ],
  "summary" : "TorBot vulnerable to Inefficient Regular Expression Complexity in validate_link",
  "details" : "### Summary\n_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.._\n\n### Details\nhttps://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13\n\nAn 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.\n\n### PoC\nI 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.\n\nFor 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.\nFor a string of size 50k, the regex will take 0.03s without the well-crafted URL and 35s with the well-crafted URL exploit.\nFor 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.\n\nThe 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.\n\n### Impact\nAn attacker could exploit this vulnerability to cause a denial of service or increased resource usage.\n",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "torbot"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "4.0.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/DedSecInside/TorBot/security/advisories/GHSA-72qw-p7hh-m3ff"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-45813"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/DedSecInside/TorBot/commit/ef6e06bc7785355b1701d5524eb4550441086ac4"
  }, {
    "type" : "WEB",
    "url" : "https://gist.github.com/ikkebr/6041055314f1cfb8e65b2a1acbaae12c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/DedSecInside/TorBot"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/DedSecInside/TorBot/blob/d2b89192379ad033ffc7044efff26e16ccc02d5a/torbot/modules/validators.py#L13"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1333" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2023-10-19T12:33:03Z",
    "nvd_published_at" : "2023-10-18T21:15:09Z"
  }
}