CVE-2008-3271 in Tomcat
Summary
by MITRE
Apache Tomcat 5.5.0 and 4.1.0 through 4.1.31 allows remote attackers to bypass an IP address restriction and obtain sensitive information via a request that is processed concurrently with another request but in a different thread, leading to an instance-variable overwrite associated with a "synchronization problem" and lack of thread safety, and related to RemoteFilterValve, RemoteAddrValve, and RemoteHostValve.
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Analysis
by VulDB Data Team • 08/18/2019
This vulnerability exists in Apache Tomcat versions 4.1.0 through 4.1.31 and 5.5.0 where concurrent request processing creates a race condition that allows attackers to bypass IP address restrictions. The flaw stems from insufficient thread synchronization mechanisms within the RemoteFilterValve, RemoteAddrValve, and RemoteHostValve components that are responsible for validating client IP addresses and enforcing access controls. When multiple requests are processed simultaneously across different threads, the instance variables that store IP address information become overwritten due to the lack of proper synchronization primitives.
The technical implementation of this vulnerability demonstrates a classic race condition scenario where the thread safety mechanisms fail to protect shared resources. During concurrent request handling, the server processes multiple requests in parallel threads that share common instance variables containing IP address validation data. When one thread completes its processing and another thread begins, the instance variables may contain stale or corrupted data from previous requests, allowing unauthorized access to protected resources. This synchronization problem specifically affects the RemoteAddrValve which validates requests based on the client's IP address, and the RemoteHostValve which performs reverse DNS lookups to validate hostnames.
The operational impact of this vulnerability is significant as it enables remote attackers to bypass access controls that are meant to restrict access based on IP addresses. An attacker could exploit this weakness to gain unauthorized access to sensitive information, bypass authentication mechanisms, or perform actions that should only be available to specific IP ranges. The vulnerability is particularly dangerous in environments where Tomcat is configured to restrict access to administrative interfaces or sensitive data based on IP addresses. This type of flaw can lead to data breaches, unauthorized system access, and potential escalation of privileges within the affected applications.
Mitigation strategies should focus on implementing proper thread synchronization mechanisms within the Tomcat valve components to prevent instance variable overwrites during concurrent request processing. Organizations should upgrade to patched versions of Apache Tomcat where the synchronization issues have been resolved and proper locking mechanisms have been implemented. Additionally, administrators should consider implementing multiple layers of security controls beyond IP-based restrictions, such as authentication mechanisms, SSL/TLS encryption, and network segmentation. The vulnerability aligns with CWE-362 which describes race conditions and CWE-367 which covers time-of-check to time-of-use flaws, both of which are addressed through proper synchronization and thread safety implementations. From an ATT&CK framework perspective, this vulnerability maps to T1071.004 for application layer protocol and T1566 for phishing, as it enables attackers to bypass network-based controls and gain access to sensitive resources that would otherwise be protected.