CVE-2013-0169 in TLS Protocol
Summary
by MITRE
The TLS protocol 1.1 and 1.2 and the DTLS protocol 1.0 and 1.2, as used in OpenSSL, OpenJDK, PolarSSL, and other products, do not properly consider timing side-channel attacks on a MAC check requirement during the processing of malformed CBC padding, which allows remote attackers to conduct distinguishing attacks and plaintext-recovery attacks via statistical analysis of timing data for crafted packets, aka the "Lucky Thirteen" issue.
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Analysis
by VulDB Data Team • 12/28/2024
The Lucky Thirteen vulnerability represents a critical timing side-channel attack targeting the Transport Layer Security and Datagram Transport Layer Security protocols. This vulnerability affects TLS versions 1.1 and 1.2 as well as DTLS versions 1.0 and 1.2 implementations across multiple cryptographic libraries including OpenSSL, OpenJDK, and PolarSSL. The flaw stems from insufficient protection mechanisms during the processing of malformed Cipher Block Chaining padding, creating a window for attackers to exploit timing variations in cryptographic operations. The vulnerability specifically targets the Message Authentication Code verification process where implementations perform different execution paths based on whether padding validation succeeds or fails, thereby leaking information through timing variations that can be statistically analyzed by adversaries.
The technical exploitation of this vulnerability relies on the fundamental principle that cryptographic implementations often execute different code paths for successful versus failed padding validation, resulting in measurable time differences that correlate to the presence or absence of valid padding. When an attacker crafts malicious packets with malformed CBC padding, they can observe the time taken to process these packets and use statistical analysis to determine whether the padding was valid, ultimately enabling them to recover plaintext data from encrypted communications. This timing differential occurs because implementations typically perform padding validation in constant time but fail to do so consistently across all execution paths, particularly when handling malformed inputs. The vulnerability is classified under CWE-310 as a weakness related to cryptographic implementation and aligns with ATT&CK technique T1071.004 for application layer protocol manipulation.
The operational impact of the Lucky Thirteen vulnerability extends beyond simple information disclosure, as it enables sophisticated plaintext recovery attacks that can compromise sensitive communications. Attackers can leverage this vulnerability to decrypt portions of encrypted traffic, potentially accessing confidential data such as session tokens, passwords, or proprietary information. The attack requires only remote access to the target system and does not require authentication, making it particularly dangerous in networked environments. The vulnerability affects a wide range of implementations, including web servers, email clients, and any system utilizing TLS or DTLS for secure communications, rendering it a significant threat to internet security infrastructure. Organizations using affected cryptographic libraries face potential data breaches and compliance violations, as the vulnerability can be exploited to undermine the confidentiality guarantees that these protocols are designed to provide.
Mitigation strategies for the Lucky Thirteen vulnerability primarily involve implementing constant-time cryptographic operations and ensuring that padding validation occurs in a consistent manner regardless of input validity. The most effective approach involves updating to patched versions of affected cryptographic libraries, with OpenSSL releasing version 1.0.1g and later containing fixes for this vulnerability. Organizations should also consider implementing additional security measures such as disabling vulnerable TLS versions, deploying intrusion detection systems to monitor for suspicious timing patterns, and conducting regular security assessments to identify potentially affected systems. The vulnerability highlights the importance of considering side-channel attacks in cryptographic implementation and underscores the need for comprehensive security testing that includes timing analysis. Network administrators should also implement monitoring solutions capable of detecting anomalous timing behavior that may indicate exploitation attempts, while security teams should develop incident response procedures specifically addressing timing-based attacks.