CVE-2013-1618 in Web Browser
Summary
by MITRE
The TLS implementation in Opera before 12.13 does not properly consider timing side-channel attacks on a MAC check operation 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, a related issue to CVE-2013-0169.
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Analysis
by VulDB Data Team • 12/27/2024
The vulnerability described in CVE-2013-1618 represents a critical flaw in the Transport Layer Security implementation within Opera web browsers prior to version 12.13. This weakness specifically targets the cryptographic operations performed during the processing of TLS records, particularly focusing on the handling of Cipher Block Chaining padding. The vulnerability stems from insufficient protection against timing side-channel attacks that exploit the temporal variations in cryptographic processing. Attackers can leverage these timing discrepancies to perform statistical analysis on the cryptographic operations, ultimately enabling them to distinguish between different plaintext values and potentially recover sensitive information from encrypted communications.
The technical flaw manifests in the MAC (Message Authentication Code) verification process within the TLS protocol implementation. When Opera processes malformed CBC (Cipher Block Chaining) padding, the cryptographic library exhibits different execution times depending on whether the padding is valid or invalid. This timing variation occurs during the MAC check operation, where valid padding typically requires fewer computational cycles than invalid padding due to early termination conditions in the verification algorithm. The vulnerability is particularly concerning because it operates at the protocol level, affecting the fundamental security guarantees provided by TLS encryption. The timing differences, though subtle, become statistically significant when analyzed over multiple requests, allowing attackers to infer information about the encrypted data being transmitted.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables sophisticated attacks that can compromise the confidentiality of encrypted communications. Remote attackers can conduct distinguishing attacks that allow them to determine whether specific plaintext values match the encrypted data, and in more advanced scenarios, they can perform plaintext-recovery attacks to reconstruct sensitive information. This weakness particularly affects web browsing sessions where users transmit sensitive data such as login credentials, personal information, or financial details through TLS-encrypted connections. The vulnerability's relationship to CVE-2013-0169 demonstrates a pattern of timing side-channel vulnerabilities in cryptographic implementations, highlighting the need for robust constant-time cryptographic operations. These attacks are particularly effective against web applications and services that rely on TLS for secure communication, making them a significant concern for organizations and individuals who depend on web browser security.
Mitigation strategies for this vulnerability require immediate browser updates to versions that address the timing side-channel issues in the TLS implementation. Security researchers recommend that users upgrade to Opera 12.13 or later, which incorporates proper constant-time implementations of cryptographic operations. Organizations should also consider implementing additional network-level protections such as intrusion detection systems that can monitor for unusual timing patterns in TLS handshakes and data transfers. The vulnerability aligns with CWE-310, which specifically addresses cryptographic issues related to timing side channels, and represents a variant of the broader category of side-channel attacks that are catalogued under ATT&CK technique T1005. Network administrators should also consider implementing certificate pinning mechanisms and additional monitoring of TLS traffic to detect potential exploitation attempts. The remediation process involves not only updating browser software but also educating users about the importance of keeping their software current and recognizing the potential risks associated with outdated cryptographic implementations.