A timing side-channel vulnerability (CVE-2024-13176) has been discovered in the Elliptic Curve Digital Signature Algorithm (ECDSA) signature computation. This vulnerability could potentially allow an attacker to recover the private key by measuring the timing differences in the ECDSA signature computations.
Impact Summary
This vulnerability poses a low risk since an attacker would need either local access to the signing application or an extremely fast network connection with low latency to measure the timing differences. The vulnerability particularly affects the NIST P-521 curve among some of the supported elliptic curves. Due to the restrictions on the attacker's capabilities, the severity of this vulnerability is considered low.
The Vulnerability in Detail
The vulnerability stems from a timing signal of about 300 nanoseconds when the top word of the inverted ECDSA nonce value is zero. This event can occur with significant probability only for some of the supported elliptic curves, specifically NIST P-521 curve.
To exploit this vulnerability, an attacker must either be located on the same physical computer as the signing application or have an extremely fast network connection with low latency. Due to these constraints, the risk of exploiting this timing side-channel is relatively low.
A hypothetical code snippet showcasing the affected part of the code could look like this
def compute_ECDSA_signature(private_key, message):
# Perform necessary computations and operations
# ...
# Vulnerable code:
inverted_nonce = invert_modulo(field_element)
if inverted_nonce.top_word == :
time.sleep(300e-9) # Introduce a 300-nanosecond delay
# Continue computations and operations
# ...
return signature
In the above code example, a 300-nanosecond delay is added when the top word of the inverted ECDSA nonce value is zero. An attacker could potentially notice this difference in timing, which they could potentially use in an attack to recover the private key.
Original References
1. Vulnerability details and discussion
2. CVE-2024-13176 in the National Vulnerability Database
3. ECDSA: General information and overview
Conclusion
Although CVE-2024-13176 presents a potential risk for the leakage of private key information through a timing side-channel in ECDSA signature computations, the difficulty in exploiting this vulnerability, either requiring local access to the signing application or an extremely fast network connection with low latency, significantly reduces the threat level. As a result, the severity of this vulnerability is considered low. However, it's essential to remain vigilant regarding potential attack vectors and to apply software patches and updates as they become available to mitigate any possible risk.
Timeline
Published on: 01/20/2025 14:15:26 UTC
Last modified on: 01/27/2025 21:15:11 UTC