EUVD-2024-37356

Comprehensive Technical Analysis of EUVD-2024-37356

1. Vulnerability Assessment and Severity Evaluation

The vulnerability described in EUVD-2024-37356 pertains to an improper escaping of output in the mod_rewrite module of Apache HTTP Server versions 2.4.59 and earlier. This flaw allows an attacker to map URLs to filesystem locations that are not intentionally reachable, potentially leading to code execution or source code disclosure. The severity of this vulnerability is rated with a CVSS Base Score of 9.1, indicating a critical risk. The CVSS vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N highlights the following characteristics:

• Attack Vector (AV:N): Network-based attack.
• Attack Complexity (AC:L): Low complexity required for exploitation.
• Privileges Required (PR:N): No privileges are required.
• User Interaction (UI:N): No user interaction is required.
• Scope (S:U): Unchanged.
• Confidentiality (C:H): High impact on confidentiality.
• Integrity (I:H): High impact on integrity.
• Availability (A:N): No impact on availability.

2. Potential Attack Vectors and Exploitation Methods

The primary attack vector involves crafting specific URLs that exploit the improper escaping in mod_rewrite rules. An attacker could:

• Map URLs to Unintended Filesystem Locations: By manipulating the URL, an attacker can access files that are not supposed to be directly reachable via URLs.
• Execute Arbitrary Code: If the server configuration allows execution of certain files, an attacker could potentially execute arbitrary code.
• Disclose Source Code: An attacker could gain access to sensitive source code files, leading to intellectual property theft or further exploitation.

3. Affected Systems and Software Versions

The vulnerability affects Apache HTTP Server versions from 2.4.0 up to and including 2.4.59. Organizations running these versions are at risk and should prioritize updating their systems.

4. Recommended Mitigation Strategies

To mitigate this vulnerability, the following steps are recommended:

• Update to the Latest Version: Upgrade to Apache HTTP Server version 2.4.60 or later, which includes the fix for this vulnerability.
• Review and Constrain Rewrite Rules: Ensure that all mod_rewrite rules are appropriately constrained and do not use unsafe backreferences or variables as the first segment of the substitution.
• Use the "UnsafePrefixStat" Flag: For configurations that require the use of potentially unsafe rewrite rules, apply the UnsafePrefixStat flag to opt back in, but ensure that the substitution is appropriately constrained.
• Regular Security Audits: Conduct regular security audits and vulnerability assessments to identify and mitigate similar issues.

5. Impact on European Cybersecurity Landscape

The European cybersecurity landscape is significantly impacted by this vulnerability due to the widespread use of Apache HTTP Server in various sectors, including government, finance, healthcare, and education. The potential for code execution and source code disclosure poses a substantial risk to data integrity, confidentiality, and overall system security. Organizations must act swiftly to patch their systems to prevent potential breaches and comply with regulatory requirements such as GDPR.

6. Technical Details for Security Professionals

For security professionals, the following technical details are crucial:

• Vulnerability Identification: The vulnerability is identified as CVE-2024-38475 and is assigned the EUVD ID EUVD-2024-37356.
• Affected Module: The mod_rewrite module in Apache HTTP Server.
• Specific Issue: Improper escaping of output in mod_rewrite rules that use backreferences or variables as the first segment of the substitution.
• Mitigation Flag: The UnsafePrefixStat flag can be used to opt back in for specific rewrite rules, but this should be done with caution and proper constraint.
• References:
  • Apache HTTP Server Security Vulnerabilities
  • NetApp Security Advisory

By understanding these details, security professionals can effectively address the vulnerability and ensure the security of their systems.

Conclusion

The vulnerability described in EUVD-2024-37356 is critical and requires immediate attention. Organizations should prioritize updating their Apache HTTP Server installations and reviewing their mod_rewrite configurations to mitigate the risk of exploitation. Regular security audits and adherence to best practices will help maintain a robust cybersecurity posture.