Description

Insertion of sensitive information into log file vulnerability in Apache Syncope. When AES key of non-standard length (not 16/24/32 bytes) is configured, Syncope will pad the provided value with random characters. The resulting key value is logged. This issue affects Apache Syncope: from 3.0.15 through 3.0.16, from 4.0.3 through 4.0.7, from 4.1.0-M0 through 4.1.2. Users are recommended to upgrade to version 4.0.8 / 4.1.3, which fix this issue.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "7.5",
  "pubDate": "2026-09-14T11:17:05.370Z",
  "pubdate": "2026-09-14T11:17:05.370Z",
  "executiveSummary": "This vulnerability involves the improper logging of sensitive cryptographic material within Apache Syncope, classified as an 'Insertion of sensitive information into log file' issue.\nThe flaw occurs during the initialization of AES encryption keys when the provided key length does not adhere to standard 16, 24, or 32-byte requirements.\nIn such instances, the application performs an automatic padding operation using random characters and inadvertently writes the resulting, fully constructed key to the system logs.\nAffected products include Apache Syncope versions 3.0.15 through 3.0.16, 4.0.3 through 4.0.7, and 4.1.0-M0 through 4.1.2.\nThe risk implication is significant, as an attacker with unauthorized access to log files—whether through secondary vulnerabilities, insecure log management infrastructure, or insider access—can retrieve the encryption key.\nExposure of this key compromises the confidentiality of all data encrypted using that specific AES instance, effectively bypassing the security controls intended to protect sensitive user or system data.\nThe exploitation does not require active network-based exploitation by an attacker; rather, it relies on the observability of system logs, making log security and integrity monitoring critical defenses.",
  "technicalDetails": "The vulnerability resides within the cryptographic configuration handling component of Apache Syncope, specifically where the application processes AES key material.\nRoot Cause: The application implements a proactive padding mechanism to normalize AES key lengths. When a user-supplied key deviates from the standard industry-accepted lengths (128-bit, 192-bit, or 256-bit), the application automatically injects random characters to reach a compliant length.\nMechanism of Exposure: During this normalization routine, the application logic incorrectly passes the final, padded key object to the logging framework before finalizing the configuration process. This results in the complete, plain-text cryptographic key being written to the application log files in a readable format.\nAttack Flow: 1. Administrator or configuration process provides an AES key of non-standard length to the Apache Syncope configuration. 2. The internal key validation and normalization function detects the length discrepancy. 3. The system executes the padding routine, appending pseudo-random bytes to the key. 4. The resultant key is logged as part of the configuration event entry. 5. An adversary gains access to the log files via log aggregation tools, local file system traversal, or unauthorized access to the log management system (e.g., ELK stack, Graylog). 6. The adversary extracts the sensitive key string. 7. The adversary uses the recovered key to perform cryptographic operations, such as decrypting encrypted database entries, credentials, or session tokens protected by the affected AES instance.\nPost-Exploitation Impact: Once the AES key is compromised, the attacker can decrypt any information protected by that key. Because this is a static key used by the application, the impact is global to all encrypted data managed by that specific instance. This facilitates lateral movement, unauthorized access to sensitive PII/credentials, and potential system takeover depending on the type of data stored.\nAffected Versions: Apache Syncope 3.0.15-3.0.16; 4.0.3-4.0.7; 4.1.0-M0-4.1.2.\nThe vulnerability is inherent to the application's internal processing logic and occurs during the initialization phase. It does not strictly require network exposure to trigger the log write, as the event is logged server-side upon configuration load."
}