Description
DomPDF before version 2.0.0 is vulnerable to PHAR deserialization due to a lack of checking on the protocol before passing it into the file_get_contents() function. An attacker who can upload files of any type to the server can pass in the phar:// protocol to unserialize the uploaded file and instantiate arbitrary PHP objects. This can lead to remote code execution, especially when DOMPdf is used with frameworks with documented POP chains like Laravel or vulnerable developer code.
EPSS Score:
4%
Comprehensive Technical Analysis of EUVD-2024-3197
1. Vulnerability Assessment and Severity Evaluation
The vulnerability described in EUVD-2024-3197 pertains to DomPDF versions prior to 2.0.0, which are susceptible to PHAR deserialization attacks. This vulnerability arises from the lack of protocol validation before passing data into the file_get_contents() function. The severity of this vulnerability is rated with a CVSS Base Score of 9.8, indicating a critical risk. The CVSS vector CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H underscores the following:
- 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 needed.
- Scope (S:U): Unchanged.
- Confidentiality (C:H): High impact on confidentiality.
- Integrity (I:H): High impact on integrity.
- Availability (A:H): High impact on availability.
2. Potential Attack Vectors and Exploitation Methods
An attacker can exploit this vulnerability by uploading a specially crafted file to the server. By leveraging the phar:// protocol, the attacker can trigger the deserialization of the uploaded file, leading to the instantiation of arbitrary PHP objects. This can result in remote code execution (RCE), especially when DomPDF is integrated with frameworks like Laravel, which have documented Property-Oriented Programming (POP) chains, or when used with vulnerable developer code.
3. Affected Systems and Software Versions
The vulnerability affects all versions of DomPDF prior to 2.0.0. Organizations using these versions, particularly those integrating DomPDF with frameworks like Laravel or other PHP applications, are at risk.
4. Recommended Mitigation Strategies
To mitigate this vulnerability, the following steps are recommended:
- Upgrade to the Latest Version: Upgrade DomPDF to version 2.0.0 or later, which includes fixes for this vulnerability.
- Input Validation: Implement strict input validation to ensure that only expected file types and protocols are processed.
- Disable PHAR Protocol: Disable the
phar://protocol if it is not required for your application. - Regular Security Audits: Conduct regular security audits and code reviews to identify and mitigate similar vulnerabilities.
- Use Security Libraries: Utilize security libraries and frameworks that provide additional layers of protection against deserialization attacks.
5. Impact on European Cybersecurity Landscape
The impact of this vulnerability on the European cybersecurity landscape is significant. Given the widespread use of PHP and frameworks like Laravel, many organizations and applications could be at risk. The high CVSS score indicates that successful exploitation could lead to severe consequences, including data breaches, unauthorized access, and service disruptions. This underscores the importance of timely patching and adherence to best security practices.
6. Technical Details for Security Professionals
For security professionals, the following technical details are pertinent:
- Vulnerability Identification: The vulnerability is identified by CVE-2021-3838 and GHSA-577p-7j7h-2jgf.
- Exploitation Mechanism: The exploitation involves uploading a malicious file and using the
phar://protocol to trigger deserialization. - Code Review: Review the codebase for any instances where
file_get_contents()is used without proper protocol validation. - Patch Analysis: The commit
99aeec1efec9213e87098d42eb09439e7ee0bb6ain the DomPDF GitHub repository addresses this issue by adding protocol checks. - References:
By understanding these details, security professionals can better assess the risk, implement appropriate mitigations, and ensure the security of their applications.
Conclusion
EUVD-2024-3197 highlights a critical vulnerability in DomPDF that can lead to remote code execution. Organizations must prioritize upgrading to the latest version of DomPDF and implement robust security measures to protect against such attacks. The European cybersecurity landscape requires vigilance and proactive measures to safeguard against the exploitation of similar vulnerabilities.