CVE-2023-51652: OWASP.AntiSamy Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-8x6f-956f-q43w
CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2023-51652 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting OWASP.AntiSamy libraries in the NuGet ecosystem. The issue involves owasp.antisamy mxss when preserving comments. Remediation is available by upgrading affected packages to version 1.2.0.

CVE-2023-51652 at a Glance

CVE Identifier CVE-2023-51652
GHSA Identifier GHSA-8x6f-956f-q43w
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product OWASP.AntiSamy
Package Ecosystem NuGet
Published Date
Last Updated

Security Impact

CVSS: 6.1

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:R/S:C/C:L/I:L/A:N).

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

How to Fix CVE-2023-51652

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

OWASP.AntiSamy fixed: 1.2.0
Upgrade OWASP.AntiSamy to 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:

inspect dependencies for OWASP.AntiSamy

How to Check if You Are Affected

To determine whether your application is affected by CVE-2023-51652, inspect your project dependencies for OWASP.AntiSamy:

inspect dependencies for OWASP.AntiSamy

Analyze the terminal output to locate any version of OWASP.AntiSamy 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: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In OWASP.AntiSamy, 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

# Impact There is a potential for a mutation XSS (mXSS) vulnerability in AntiSamy caused by flawed parsing of the HTML being sanitized. To be subject to this vulnerability the `preserveComments` directive must be enabled in your policy file and also allow for certain tags at the same time. As a result, certain crafty inputs can result in elements in comment tags being interpreted as executable when using AntiSamy's sanitized output. # Patches Patched in OWASP AntiSamy .NET 1.2.0 and later. See important remediation details in the reference given below. # Workarounds If you cannot upgrade to a fixed version of the library, the following mitigation can be applied until you can upgrade: Manually edit your AntiSamy policy file (e.g., antisamy.xml) by deleting the `preserveComments` directive or setting its value to `false`, if present. Also it would be useful to make AntiSamy remove the `noscript` tag by adding this in your tag definitions under the `<tagrules>` node (or deleting it entirely if present): ```xml <tag name="noscript" action="remove"/> ``` As the previously mentioned policy settings are preconditions for the mXSS attack to work, changing them as recommended should be sufficient to protect you against this vulnerability when using a vulnerable version of this library. However, the existing bug would still be present in AntiSamy or its parser dependency (HtmlAgilityPack). The safety of this workaround relies on configurations that may change in the future and don't address the root cause of the vulnerability. As such, it is strongly recommended to upgrade to a fixed version of AntiSamy. # For more information If you have any questions or comments about this advisory: Email one of the project co-leaders, listed on the [OWASP AntiSamy project](https://owasp.org/www-project-antisamy/) page, under "Leaders".

CVE-2023-51652 Affected OWASP.AntiSamy Versions

1 component(s)
Fixed Versions:
1.2.0
Product / Package Ecosystem Affected Versions Fixed Version
OWASP.AntiSamy
NuGet
< 1.2.0
1.2.0

References

Frequently Asked Questions

What is CVE-2023-51652?
CVE-2023-51652 is a security vulnerability in OWASP.AntiSamy involving OWASP.AntiSamy mXSS when preserving comments under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which OWASP.AntiSamy versions are affected?
Affected versions include releases prior to 1.2.0 across affected packages: OWASP.AntiSamy.
What version fixes CVE-2023-51652?
Upgrading to 1.2.0 (or the latest patched release for your respective branch) resolves the vulnerability.
Is OWASP.AntiSamy affected?
Yes, OWASP.AntiSamy 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-2023-51652?
CVE-2023-51652 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2023-51652?
CVE-2023-51652 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check NuGet dependencies for CVE-2023-51652?
Run the dependency tree command: 'inspect dependencies for OWASP.AntiSamy'. 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
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-8x6f-956f-q43w",
  "modified" : "2024-01-02T23:28:07Z",
  "published" : "2024-01-02T16:38:28Z",
  "aliases" : [ "CVE-2023-51652" ],
  "summary" : "OWASP.AntiSamy mXSS when preserving comments",
  "details" : "# Impact\n\nThere is a potential for a mutation XSS (mXSS) vulnerability in AntiSamy caused by flawed parsing of the HTML being sanitized. To be subject to this vulnerability the `preserveComments` directive must be enabled in your policy file and also allow for certain tags at the same time. As a result, certain crafty inputs can result in elements in comment tags being interpreted as executable when using AntiSamy's sanitized output.\n\n# Patches\n\nPatched in OWASP AntiSamy .NET 1.2.0 and later. See important remediation details in the reference given below.\n\n# Workarounds\n\nIf you cannot upgrade to a fixed version of the library, the following mitigation can be applied until you can upgrade: Manually edit your AntiSamy policy file (e.g., antisamy.xml) by deleting the `preserveComments` directive or setting its value to `false`,  if present. Also it would be useful to make AntiSamy remove the `noscript` tag by adding this in your tag definitions under the `<tagrules>` node (or deleting it entirely if present):\n```xml\n<tag name=\"noscript\" action=\"remove\"/>\n```\n\nAs the previously mentioned policy settings are preconditions for the mXSS attack to work, changing them as recommended should be sufficient to protect you against this vulnerability when using a vulnerable version of this library. However, the existing bug would still be present in AntiSamy or its parser dependency (HtmlAgilityPack). The safety of this workaround relies on configurations that may change in the future and don't address the root cause of the vulnerability. As such, it is strongly recommended to upgrade to a fixed version of AntiSamy.\n\n# For more information\n\nIf you have any questions or comments about this advisory:\n\nEmail one of the project co-leaders, listed on the [OWASP AntiSamy project](https://owasp.org/www-project-antisamy/) page, under \"Leaders\".",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "NuGet",
      "name" : "OWASP.AntiSamy"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.2.0"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/spassarop/antisamy-dotnet/security/advisories/GHSA-8x6f-956f-q43w"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2023-51652"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/spassarop/antisamy-dotnet/commit/7e500daef6ad9c10e97c68feab78f4cb6e3083c6"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/spassarop/antisamy-dotnet/commit/8117911933e75a25cd0054ef017577486338444a"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/spassarop/antisamy-dotnet"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2024-01-02T16:38:28Z",
    "nvd_published_at" : "2024-01-02T20:15:10Z"
  }
}