CVE-2021-28170 affects the Jakarta Expression Language implementation 3.0.3 and earlier. This vulnerability allows invalid EL expressions to be evaluated as if they were valid due to a bug in the ELParserTokenManager. The severity of this vulnerability is classified as medium, with a CVSS score of 5.3.
The risk to organizations includes potential data integrity issues, as invalid expressions can lead to unintended behavior within applications that utilize this component. As such, it is crucial for affected organizations to prioritize the application of patches to mitigate exploitation risks.
Currently, there are no known exploits or public proof of concepts available for this vulnerability. However, organizations should remain vigilant and monitor for any updates regarding the security status of the Jakarta Expression Language.
Organizations should prioritize patching immediately, especially those using versions prior to 3.0.3, to protect against potential exploitation.
Vulnerability Details
In the Jakarta Expression Language implementation 3.0.3 and earlier, a bug in the ELParserTokenManager enables invalid EL expressions to be evaluated as if they were valid. This vulnerability has been classified under CWE-20 (Improper Input Validation) and CWE-917 (Improper Neutralization of Input During Web Page Generation).
The CVSS score for this vulnerability is 5.3, indicating a medium severity. The attack vector is network-based, with low complexity and no privileges required for exploitation. User interaction is also not required.
The affected products include the Jakarta Expression Language, Quarkus, Oracle's Communications Cloud Native Core Policy, and WebLogic Server.
Technical Analysis
The root cause of this vulnerability lies in the ELParserTokenManager's handling of EL expressions. Invalid expressions should have been rejected but due to a bug, they are processed as valid. This flaw creates a vector for potential integrity issues within applications that rely on this functionality.
The attack vector is network-based, meaning that an attacker could potentially exploit this vulnerability remotely without the need for direct access to the system. The attack complexity is low, as no special conditions must be met to exploit this vulnerability. Additionally, no privileges are required, and user interaction is not needed, making it easier for attackers to exploit.
In terms of impact, the confidentiality of information is not affected, but there is a low integrity impact, which means that the correctness of data could be compromised. There is no availability impact associated with this vulnerability.
Risk & Impact Analysis
Real-world deployment risk is significant due to the nature of the vulnerability. Applications utilizing the Jakarta Expression Language could process invalid expressions, leading to unexpected behavior and potential data integrity issues. This is particularly concerning in environments where application logic is dependent on correct EL evaluations.
The blast radius could be extensive, affecting any application that relies on the Jakarta Expression Language across various industries. Given the low complexity of exploitation and the lack of required privileges, organizations utilizing affected versions must act promptly.
With a CVSS score of 5.3, the urgency assessment indicates that organizations should address this vulnerability in their priority patch cycle. Monitoring for any updates related to this vulnerability is also recommended.
Exploitation Status
Signal | Status |
|---|---|
Known Exploit | No |
Public PoC | No |
Actively Exploited | No |
Ransomware Use | No |
Affected Versions
The following versions are affected by this vulnerability: Jakarta Expression Language 3.0.3 and earlier, Quarkus versions prior to 2.3.0, Oracle Communications Cloud Native Core Policy 1.14.0, and Oracle WebLogic Server 14.1.1.0.0.
Mitigation & Remediation
To mitigate the risks associated with this vulnerability, organizations should apply the latest patches provided by the vendors. Specifically, updating to the patched versions of Jakarta Expression Language, Quarkus, and WebLogic Server is crucial.
For environments where immediate patching is not possible, organizations should implement input validation and sanitization mechanisms to prevent malicious EL expressions from being executed.
Regular security assessments, such as penetration testing, should be performed to identify and remediate similar vulnerabilities.
Detection Guidance
Monitoring logs for unexpected EL expression evaluations can help in detecting potential exploitation attempts. Additionally, organizations should look for behavioral anomalies in application responses that could indicate misuse of the EL functionality.
Implementing network signatures that recognize patterns associated with invalid EL expressions can also aid in early detection.
AppSecure Threat Intelligence Insight
CVE-2021-28170 represents a critical reminder of the importance of rigorous input validation within application security. The patterns observed in this vulnerability highlight the need for ongoing vigilance in software development practices.
The vulnerability emphasizes the necessity for security teams to conduct thorough code reviews and testing to identify similar weaknesses in the development lifecycle.
Organizations should consider adopting a comprehensive vulnerability management program to effectively manage and remediate vulnerabilities.
Moreover, organizations should invest in penetration testing methodology training to ensure their development and security teams are equipped with the necessary skills to identify and mitigate vulnerabilities effectively.
Finally, organizations should leverage web application penetration testing to continuously assess their applications against evolving threats.
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
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