CVE-2023-24814 : Exploit Details and Defense Strategies

This CVE involves a persisted Cross-Site Scripting vulnerability in TYPO3 due to improper neutralization of input during web page generation. Attackers can inject malicious content via the TYPO3 core component

GeneralUtility::getIndpEnv()

using unfiltered server environment variables, potentially resulting in the injection of malicious HTML code to uncached pages and persistence of cross-site scripting.

Understanding CVE-2023-24814

This section aims to delve deeper into the nature of the CVE and its impact.

What is CVE-2023-24814?

In affected versions of TYPO3, the vulnerability arises from the handling of the server environment variable

PATH_INFO

by the

GeneralUtility::getIndpEnv()

function. By leveraging the TypoScript setting

config.absRefPrefix=auto

, attackers can inject malicious HTML code, which gets cached and distributed to other users, leading to persisted cross-site scripting.

The Impact of CVE-2023-24814

The vulnerability exposes websites to the risk of cross-site scripting attacks. Notably, Apache web server deployments using CGI like FPM, FCGI, and similar technologies are confirmed to be affected. However, there remains a potential risk for other scenarios such as nginx, IIS, or Apache/mod_php.

Technical Details of CVE-2023-24814

This section will provide a technical overview of the vulnerability, including its description, affected systems and versions, and exploitation mechanism.

Vulnerability Description

The vulnerability allows attackers to inject malicious content through the

GeneralUtility::getIndpEnv()

function, enabling persistent cross-site scripting on TYPO3 websites.

Affected Systems and Versions

TYPO3 versions including

8.7.0

to

< 8.7.51

,

9.0.0

to

< 9.5.40

,

10.0.0

to

< 10.4.36

,

11.0.0

to

< 11.5.23

, and

12.0.0

to

< 12.2.0

are confirmed to be affected by this vulnerability.

Exploitation Mechanism

Attackers can exploit the vulnerability by injecting malicious HTML code through the unfiltered server variable

PATH_INFO

, combined with the TypoScript setting

config.absRefPrefix=auto

, resulting in persisting cross-site scripting attacks.

Mitigation and Prevention

This section covers the steps users can take to mitigate the impact of CVE-2023-24814 and prevent such vulnerabilities in the future.

Immediate Steps to Take

Users are advised to update to patched TYPO3 versions, which include

8.7.51 ELTS

,

9.5.40 ELTS

,

10.4.35 LTS

,

11.5.23 LTS

, and

12.2.0

to fix this vulnerability. Alternatively, setting the TypoScript

config.absRefPrefix

to a static path value can offer an interim mitigation measure, although this does not address all aspects of the vulnerability.

Long-Term Security Practices

It is crucial for organizations to prioritize regular security updates, conduct security audits, and adhere to secure coding practices to mitigate the risk of similar vulnerabilities in the future.

Patching and Updates

Regularly updating TYPO3 installations and applying security patches promptly is essential to ensure the system is protected against known vulnerabilities and exploits.