CVE-2021-28170 : What You Need to Know

This article provides insights into CVE-2021-28170, focusing on the Jakarta Expression Language Implementation vulnerability and its impact on affected systems.

Understanding CVE-2021-28170

CVE-2021-28170 highlights a vulnerability in the Jakarta Expression Language Implementation, affecting versions 3.0.3 and earlier.

What is CVE-2021-28170?

A bug in the ELParserTokenManager in versions up to 3.0.3 allows invalid EL expressions to be mistakenly evaluated as valid, posing a security risk.

The Impact of CVE-2021-28170

This vulnerability can be exploited by attackers to execute arbitrary code or conduct denial-of-service attacks, compromising the integrity of affected systems.

Technical Details of CVE-2021-28170

Here are the technical aspects of the CVE-2021-28170 vulnerability:

Vulnerability Description

The flaw in the ELParserTokenManager module allows malicious actors to craft and pass invalid EL expressions as legitimate, leading to security breaches.

Affected Systems and Versions

The Jakarta Expression Language Implementation versions earlier than 3.0.3 are susceptible to this vulnerability, requiring immediate attention and mitigation.

Exploitation Mechanism

Attackers can exploit this vulnerability by submitting specially crafted input through EL expressions, granting them unauthorized access and control over the application.

Mitigation and Prevention

To address CVE-2021-28170, organizations and users should take the following steps:

Immediate Steps to Take

Update the Jakarta Expression Language Implementation to version 3.0.3 or later to patch the vulnerability.
Monitor system logs for any suspicious activities indicating exploitation attempts.

Long-Term Security Practices

Regularly audit and review input validation mechanisms to prevent similar vulnerabilities.
Implement strict input validation and output encoding practices to mitigate injection attacks.

Patching and Updates

Stay informed about security advisories from Eclipse Foundation and other relevant sources to apply patches promptly and secure your systems.