An issue was discovered in TCPDF before 6.8.0. The function unserializeTCPDFtag uses loose comparison and does not employ a constant-time function to compare TCPDF tag hashes. This design flaw can lead to serious security implications.
With a CVSS score of 7.5, this vulnerability is categorized as high severity. Organizations using affected versions of TCPDF should take this issue seriously, as it poses a substantial risk to confidentiality.
Risk to organizations includes potential unauthorized access to sensitive information, as attackers may leverage this vulnerability to manipulate the comparison of tag hashes within the library.
Organizations should prioritize patching immediately. The risk of exploitation exists, and while there are no known exploits publicly available at this time, the potential for future exploitation remains.
Vulnerability Details
The vulnerability in TCPDF is fundamentally due to the use of loose comparison operators in the unserializeTCPDFtag function, which fails to employ a secure method for hash comparison.
The CVSS vector for this vulnerability is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N, indicating that it has a high confidentiality impact with no integrity or availability impact.
The affected product is tcpdf, specifically versions prior to 6.8.0. The vulnerability was published on December 27, 2024.
This vulnerability is classified under CWE-843, which pertains to the improper neutralization of special elements used in a command.
Technical Analysis
The root cause of this vulnerability lies in the design choices made in the TCPDF library, specifically in how it handles comparison operations for tag hashes. By utilizing loose comparison rather than a secure, constant-time comparison, the library is vulnerable to timing attacks.
The attack vector is network-based, meaning that an attacker can exploit this vulnerability remotely without needing to be in the same physical location as the target system. The complexity of the attack is low, requiring no special privileges or user interaction.
The confidentiality impact is high, as successful exploitation could lead to unauthorized access to sensitive data. However, the integrity and availability impacts are negligible.
Risk & Impact Analysis
The real-world deployment risk for this vulnerability is significant, particularly for organizations that rely on TCPDF for document generation or processing. The potential for unauthorized access to confidential documents poses a serious threat.
This matters to organizations as the confidentiality of documents is paramount. If an attacker can exploit this vulnerability, they can manipulate or extract sensitive information, leading to data breaches.
The blast radius of this vulnerability is considerable, affecting all users of the affected TCPDF versions. Urgency for remediation is high, as the potential impact is severe, and organizations should schedule remediation as soon as possible.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
All versions prior to vendor patch 6.8.0 are affected. Organizations using older versions of TCPDF should upgrade to version 6.8.0 or later.
Mitigation & Remediation
Organizations should upgrade to TCPDF version 6.8.0 or later to mitigate this vulnerability. It is crucial to apply the patch as soon as possible to prevent potential exploitation.
In addition to upgrading, organizations may consider implementing configuration hardening and network controls to further secure their systems.
For continuous security and vulnerability assessments, organizations should engage in continuous penetration testing to ensure that all security measures are effective.
Detection Guidance
Organizations should monitor logs for any unusual activity related to TCPDF usage. Behavioral anomalies or changes in system behavior could indicate attempts to exploit this vulnerability.
Implementing network signatures that can detect unauthorized access attempts will also be beneficial in identifying potential exploitation.
AppSecure Threat Intelligence Insight
The long-term significance of this vulnerability is that it highlights the importance of using secure comparison methods in software development. Security teams should be vigilant about similar design flaws in other libraries.
This vulnerability represents a pattern of vulnerabilities that arise from improper handling of data types in programming. Organizations should incorporate secure coding practices to mitigate similar risks.
For further insights on securing applications, organizations can refer to our comprehensive resources on penetration testing methodology and vulnerability management program design to enhance security posture.
To further strengthen security measures, organizations can consider engaging in red teaming services which simulate real-world attacks.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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