CVE-2022-36436: Vncauthproxy Authentication Bypass Vulnerability

CRITICAL
Advisory Identifier: GHSA-237r-mx84-7x8c
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CVSS 9.8
CWE-287
Published
Advisory Summary

CVE-2022-36436 is a CRITICAL (CVSS 9.8) authentication bypass vulnerability (CWE-287: Improper Authentication) affecting Vncauthproxy libraries in the PyPI ecosystem. The issue involves vncauthproxy authentication bypass vulnerability. Remediation is available by upgrading affected packages to version 1.2.0.

CVE-2022-36436 at a Glance

CVE Identifier CVE-2022-36436
GHSA Identifier GHSA-237r-mx84-7x8c
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-287: Improper Authentication
Affected Product Vncauthproxy
Package Ecosystem PyPI
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

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

How to Fix CVE-2022-36436

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

vncauthproxy fixed: 1.2.0 
pip install vncauthproxy>=1.2.0
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 vncauthproxy

How to Check if You Are Affected

To determine whether your Python environment is affected by CVE-2022-36436, inspect your installed packages using pip:

pip show vncauthproxy

Analyze the terminal output to locate any version of Vncauthproxy in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.2.0), your application is affected.

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

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-287: Improper Authentication, where when an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. In Vncauthproxy, 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

OSU Open Source Lab VNCAuthProxy through 1.1.1 is affected by an vncap/vnc/protocol.py VNCServerAuthenticator authentication-bypass vulnerability that could allow a malicious actor to gain unauthorized access to a VNC session or to disconnect a legitimate user from a VNC session. A remote attacker with network access to the proxy server could leverage this vulnerability to connect to VNC servers protected by the proxy server without providing any authentication credentials. Exploitation of this issue requires that the proxy server is currently accepting connections for the target VNC server.

CVE-2022-36436 Affected Vncauthproxy Versions

1 component(s)
Fixed Versions:
1.2.0
Product / Package Ecosystem Affected Versions Fixed Version
vncauthproxy
pypi/vncauthproxy
PyPI
< 1.2.0
1.2.0

References

NVD — CVE-2022-36436 NVD
https://nvd.nist.gov/vuln/detail/CVE-2022-36436
Security Fix Commit FIX COMMIT
https://github.com/osuosl/twisted_vncauthproxy/commit/edc149af29242178091b2d6fcd42c3ef0851644b
cert.grnet.gr/en/blog/cve-2022-36... WEB
https://cert.grnet.gr/en/blog/cve-2022-36436-twisted-vnc-authentication-proxy-authentication-bypass
Vncauthproxy Source Repository REPOSITORY
https://github.com/osuosl/twisted_vncauthproxy
Vncauthproxy Source Repository REPOSITORY
https://github.com/osuosl/twisted_vncauthproxy/tree/release/1.1.1
Vncauthproxy Source Repository REPOSITORY
https://github.com/pypa/advisory-database/tree/main/vulns/vncauthproxy/PYSEC-2022-267.yaml
pypi.org/project/vncauthprox... WEB
https://pypi.org/project/VNCAuthProxy

Frequently Asked Questions

What is CVE-2022-36436?
CVE-2022-36436 is a security vulnerability in Vncauthproxy involving VNCAuthProxy authentication bypass vulnerability under CWE-287: Improper Authentication.
Which Vncauthproxy versions are affected?
Affected versions include releases prior to 1.2.0 across affected packages: vncauthproxy.
What version fixes CVE-2022-36436?
Upgrading to 1.2.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is vncauthproxy affected?
Yes, vncauthproxy is affected in releases prior to 1.2.0. Upgrade your dependency to 1.2.0 or later.
What is the CVSS score of CVE-2022-36436?
CVE-2022-36436 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2022-36436?
CVE-2022-36436 is classified under CWE-287: Improper Authentication (When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.).
How can I check PyPI dependencies for CVE-2022-36436?
Run the dependency tree command: 'pip show vncauthproxy'. 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-237r-mx84-7x8c",
  "modified" : "2024-11-18T23:04:06Z",
  "published" : "2022-09-16T17:11:31Z",
  "aliases" : [ "CVE-2022-36436" ],
  "summary" : "VNCAuthProxy authentication bypass vulnerability",
  "details" : "OSU Open Source Lab VNCAuthProxy through 1.1.1 is affected by an vncap/vnc/protocol.py VNCServerAuthenticator authentication-bypass vulnerability that could allow a malicious actor to gain unauthorized access to a VNC session or to disconnect a legitimate user from a VNC session. A remote attacker with network access to the proxy server could leverage this vulnerability to connect to VNC servers protected by the proxy server without providing any authentication credentials. Exploitation of this issue requires that the proxy server is currently accepting connections for the target VNC server.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "PyPI",
      "name" : "vncauthproxy"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.2.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2022-36436"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/osuosl/twisted_vncauthproxy/commit/edc149af29242178091b2d6fcd42c3ef0851644b"
  }, {
    "type" : "WEB",
    "url" : "https://cert.grnet.gr/en/blog/cve-2022-36436-twisted-vnc-authentication-proxy-authentication-bypass"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/osuosl/twisted_vncauthproxy"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/osuosl/twisted_vncauthproxy/tree/release/1.1.1"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/pypa/advisory-database/tree/main/vulns/vncauthproxy/PYSEC-2022-267.yaml"
  }, {
    "type" : "WEB",
    "url" : "https://pypi.org/project/VNCAuthProxy"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-287" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2022-09-16T17:11:31Z",
    "nvd_published_at" : "2022-09-14T11:15:00Z"
  }
}