CVE-2017-2598 in Jenkins
Summary
by MITRE
Jenkins before versions 2.44, 2.32.2 uses AES ECB block cipher mode without IV for encrypting secrets which makes Jenkins and the stored secrets vulnerable to unnecessary risks (SECURITY-304).
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Analysis
by VulDB Data Team • 03/14/2023
The vulnerability identified as CVE-2017-2598 represents a critical cryptographic weakness in Jenkins continuous integration platform versions prior to 2.44 and 2.32.2. This flaw resides in the encryption implementation used for storing sensitive secrets within the Jenkins environment, creating a significant security risk that affects organizations relying on Jenkins for automated build and deployment processes. The vulnerability stems from the use of Advanced Encryption Standard (AES) in Electronic Codebook (ECB) mode without initialization vectors, which fundamentally undermines the security guarantees that proper encryption should provide.
The technical flaw manifests in Jenkins' approach to secret encryption where the system employs AES encryption in ECB mode, a block cipher mode that processes each data block independently without any chaining mechanism. This approach creates predictable encryption patterns that can be exploited by attackers to gain insights into the encrypted data. Without initialization vectors, identical plaintext blocks will always produce identical ciphertext blocks, making the encrypted secrets susceptible to pattern analysis and cryptanalysis techniques. The absence of IVs eliminates the randomness that is essential for secure encryption, rendering the encryption mechanism vulnerable to various attacks including frequency analysis and pattern recognition.
The operational impact of this vulnerability extends beyond simple data confidentiality breaches, as it compromises the entire security posture of Jenkins installations that store sensitive information such as passwords, API keys, and other credentials. Attackers who gain access to the encrypted secrets can potentially reconstruct the original sensitive data through various cryptanalytic methods, particularly when the same secrets are used across multiple contexts or when attackers can observe multiple encrypted instances of similar data. This vulnerability affects not only the confidentiality of stored secrets but also undermines the trust that organizations place in Jenkins as a secure platform for managing automated processes and sensitive information.
Organizations should implement immediate mitigations including upgrading to Jenkins versions 2.44 or 2.32.2 where the encryption mechanism has been properly addressed. The fix involves transitioning from ECB mode to authenticated encryption modes such as CBC or GCM that incorporate proper initialization vectors and provide better security guarantees. Security teams should also conduct comprehensive audits of all stored secrets and consider re-encrypting existing data with the corrected encryption implementation. Additionally, implementing proper access controls and monitoring for unauthorized access attempts to Jenkins systems can help detect potential exploitation attempts. This vulnerability aligns with CWE-327, which addresses the use of weak encryption algorithms and improper implementation of cryptographic functions, and corresponds to ATT&CK technique T1552.001 for unsecured credentials and T1552.006 for data manipulation. The remediation process should include verifying that all Jenkins configurations and plugins that handle sensitive data properly implement secure encryption practices moving forward.