ECDSA Timing Side-Channel Vulnerability in OpenSSL Library

CVE-2024-13176

What is CVE-2024-13176?

CVE-2024-13176 is a vulnerability found in the OpenSSL library, specifically concerning the ECDSA (Elliptic Curve Digital Signature Algorithm) signature computation. OpenSSL is a widely-used cryptographic library essential for securing communications over the internet. This vulnerability presents a timing side-channel risk that could potentially allow an attacker to recover a private key, posing a threat to the confidentiality and integrity of sensitive data and communications for organizations relying on OpenSSL for secure transaction processing and data encryption.

Technical Details

The vulnerability arises from the manner in which the ECDSA signature computations are handled. It allows an attacker to exploit timing discrepancies, specifically a 300-nanosecond signature time leak that occurs when the top word of the ECDSA nonce value is zero. This behavior is observed primarily with the NIST P-521 elliptic curve. To successfully exploit this vulnerability, an attacker must either have physical access to the signing application or maintain a low-latency, high-speed network connection capable of accurately measuring the timing signals. Due to these stringent requirements, the vulnerability’s severity is classified as low.

Potential Impact of CVE-2024-13176

1. Private Key Recovery: The main risk presented by this vulnerability is the potential for an attacker to recover private keys. If a private key is compromised, it can lead to unauthorized access to secure communications and data, severely damaging the integrity and confidentiality of sensitive information.

2. Risk of Data Breach: Organizations utilizing ECDSA for secure transactions may face increased risks of data breaches. The ability to extract private keys enables attackers to intercept encrypted communications, leading to potential leaks of confidential information.

3. Increased Attack Surface: The existence of this vulnerability creates an increased attack surface for organizations that utilize OpenSSL, particularly those using the affected elliptic curves. This vulnerability can serve as an entry point for further attacks, exacerbating overall security risks.

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