CVE-2020-25633 in RESTEasy
Summary
by MITRE
A flaw was found in RESTEasy client in all versions of RESTEasy up to 4.5.6.Final. It may allow client users to obtain the server's potentially sensitive information when the server got WebApplicationException from the RESTEasy client call. The highest threat from this vulnerability is to data confidentiality.
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Analysis
by VulDB Data Team • 03/14/2025
This vulnerability exists within the RESTEasy client implementation across all versions up to 4.5.6.Final, representing a significant confidentiality risk in web application security. The flaw manifests when a WebApplicationException is thrown during client-server communication, potentially exposing sensitive server information to unauthorized parties. This represents a classic information disclosure vulnerability that can compromise data integrity and confidentiality principles. The vulnerability falls under CWE-200, which specifically addresses information exposure, and aligns with ATT&CK technique T1213.002 for data from information repositories, indicating how attackers could leverage this weakness to extract sensitive data.
The technical implementation of this vulnerability stems from improper handling of exception responses within the RESTEasy client library. When a WebApplicationException occurs during a client call, the library fails to properly sanitize or filter the response data before returning it to the calling application. This creates an unintended information leak where sensitive server-side details, potentially including internal error messages, stack traces, or other confidential data, become accessible to client applications that process these exceptions. The flaw essentially allows a cascading information disclosure scenario where the originally intended error handling mechanism becomes a vector for data exfiltration.
The operational impact of this vulnerability extends beyond simple data exposure, as it can enable more sophisticated attacks by providing attackers with additional context about the target system. An attacker could potentially exploit this vulnerability to gather information about the server's internal structure, application architecture, or even specific implementation details that could aid in subsequent attacks. This weakness particularly affects applications that rely heavily on RESTEasy for client-server communication and may be exploited in conjunction with other vulnerabilities to escalate privileges or gain deeper system access. The confidentiality threat level is elevated because the information disclosed could include sensitive system details that would normally be protected from external access.
Mitigation strategies for this vulnerability should focus on immediate version upgrades to RESTEasy 4.5.7.Final or later, which contain the necessary patches to address the improper exception handling. Organizations should also implement comprehensive input validation and output sanitization measures within their applications to reduce the impact of any potential exploitation attempts. Additionally, network segmentation and access controls should be reviewed to limit the potential damage from information disclosure. Security monitoring should be enhanced to detect unusual patterns in error response handling that might indicate exploitation attempts. The vulnerability highlights the importance of proper exception management in web applications and underscores the need for thorough security testing of client libraries, particularly those handling sensitive data exchanges.