IBM WebSphere RCE Java Deserialization Vulnerability
Description
IBM WebSphere Application Server versions 7.0 and later contain a critical vulnerability in their handling of Java object deserialization. The vulnerability stems from the use of Apache Commons Collections library, which allows untrusted data to be deserialized using the dangerous InvokerTransformer class. When an application deserializes untrusted input without proper validation, attackers can craft malicious serialized objects that execute arbitrary code upon deserialization. This vulnerability does not affect IBM HTTP Server or WebSphere Application Server versions prior to 7.0.
Remediation
Take the following steps to remediate this vulnerability:
1. Immediate Action:
• Apply the security patches provided by IBM as documented in Security Bulletin swg21970575
• Upgrade to a patched version of WebSphere Application Server that addresses CVE-2015-7450
2. Verify Remediation:
• Test that deserialization endpoints no longer accept malicious payloads
• Confirm the Apache Commons Collections library has been updated or the vulnerable classes have been removed
3. Long-term Mitigation:
• Implement deserialization filters to whitelist only expected classes
• Avoid deserializing untrusted data whenever possible
• Consider using safer data formats such as JSON instead of Java serialization
• Monitor and log deserialization activities for suspicious patterns
Consult IBM's official security bulletin at https://www-01.ibm.com/support/docview.wss?uid=swg21970575 for version-specific patch information and detailed upgrade instructions.