CVE-2009-1378 in OpenSSL
Summary
by MITRE
Multiple memory leaks in the dtls1_process_out_of_seq_message function in ssl/d1_both.c in OpenSSL 0.9.8k and earlier 0.9.8 versions allow remote attackers to cause a denial of service (memory consumption) via DTLS records that (1) are duplicates or (2) have sequence numbers much greater than current sequence numbers, aka "DTLS fragment handling memory leak."
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Analysis
by VulDB Data Team • 11/29/2024
The vulnerability identified as CVE-2009-1378 represents a critical memory management flaw within the OpenSSL implementation of the Datagram Transport Layer Security protocol. This issue affects OpenSSL versions 0.9.8k and earlier, specifically targeting the dtls1_process_out_of_seq_message function located in the ssl/d1_both.c source file. The flaw manifests when the system processes DTLS records that either constitute duplicates of previously received messages or contain sequence numbers that are significantly higher than the current expected sequence number within the DTLS communication stream. The vulnerability operates at the protocol level where DTLS fragments are handled, creating a scenario where memory allocation occurs without proper deallocation, leading to progressive memory consumption over time.
The technical implementation of this vulnerability stems from inadequate memory management practices within the DTLS fragment processing logic. When duplicate DTLS records are received, the system allocates memory to process these records but fails to properly release the allocated memory resources when handling out-of-sequence messages. Similarly, when sequence numbers are much greater than the current sequence numbers, the function attempts to store and process these records without appropriate memory cleanup mechanisms. This behavior creates a memory leak pattern where each processed out-of-sequence record consumes additional memory without corresponding release operations. The vulnerability is particularly dangerous because it can be exploited remotely without requiring authentication or specialized privileges, making it accessible to any attacker capable of sending DTLS packets to the targeted system.
The operational impact of this vulnerability extends beyond simple resource exhaustion, creating significant risks for systems running vulnerable OpenSSL implementations. An attacker can continuously send specially crafted DTLS records with duplicate or high sequence numbers, causing the target system to gradually consume all available memory resources. This memory consumption leads to system instability, application crashes, and ultimately complete denial of service for legitimate users. The vulnerability affects any service or application that relies on OpenSSL for DTLS communication, including web servers, email servers, VPN services, and other network applications that utilize DTLS for secure communication. The memory leak occurs incrementally, meaning that the system may appear stable initially but will eventually become unresponsive as memory consumption reaches critical levels.
Mitigation strategies for CVE-2009-1378 require immediate attention and systematic implementation across affected systems. The primary and most effective solution involves upgrading to OpenSSL version 0.9.8l or later, which includes patches specifically addressing the memory leak in the dtls1_process_out_of_seq_message function. Organizations should conduct comprehensive vulnerability assessments to identify all systems running vulnerable OpenSSL versions and prioritize patch deployment. Additionally, network administrators should implement monitoring solutions to detect unusual memory consumption patterns that may indicate exploitation attempts. The vulnerability aligns with CWE-401, which specifically addresses improper release of memory, and represents a classic example of memory leak exploitation. From an ATT&CK framework perspective, this vulnerability maps to the T1499.004 technique related to network denial of service, as it specifically targets memory exhaustion to achieve denial of service conditions. Network segmentation and rate limiting of DTLS traffic can serve as temporary mitigation measures while permanent patches are deployed, though these approaches do not address the root cause of the memory leak within the OpenSSL implementation.