CVE-2024-58262: Constant-Time Operation Removal in curve25519-dalek Crate Exposes Timing Side-Channel

The curve25519-dalek crate is a popular Rust library for elliptic-curve cryptography. A newly disclosed vulnerability, CVE-2024-58262, reveals a potential timing side-channel attack due to LLVM optimization removing constant-time operations on elliptic curve scalars. This can leak sensitive information about the cryptographic keys being used.

Vulnerability Details

• CVE ID: CVE-2024-58262
• Description: The curve25519-dalek crate before version 4.1.3 for Rust exhibits a vulnerability where a constant-time operation on elliptic curve scalars is unintentionally removed by the LLVM compiler. This removal introduces timing variations that could be exploited by attackers to infer information about the private keys used in cryptographic operations.
• CVSS Score and Vector:
  • CVSS Score: 2.9 (Low)
  • CVSS Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
  • Explanation: A low CVSS score means this vulnerability requires local access (AV:L) and high attack complexity (AC:H). While confidentiality is affected (C:L), there's no impact on integrity (I:N) or availability (A:N). The attacker needs to be on the same system and must carefully measure timing differences, but the potential impact is information disclosure.
• Exploit Requirements: An attacker needs local access to the system and the ability to precisely measure the execution time of cryptographic operations using the vulnerable curve25519-dalek library.
• Affected Vendor, Product, Version:
  • Vendor: N/A (Vulnerability in a Rust crate)
  • Product: curve25519-dalek
  • Version: Before 4.1.3
• CWE:
  • CWE ID: CWE-733
  • CWE Name: Weaknesses in Cryptographic Routines
  • Explanation: This CWE indicates that the cryptographic routines have weaknesses, such as timing vulnerabilities, that may allow attackers to break the cryptography or otherwise circumvent the expected security properties. In this specific case, the weakness is that a constant-time operation intended to prevent timing attacks has been removed by compiler optimization.

Timeline of Events

• 2024: Vulnerability introduced in versions prior to 4.1.3.
• 2024: Vulnerability discovered and reported.
• 2025-07-27: CVE-2024-58262 assigned.
• 2025-07-27: Public disclosure.

Exploitability & Real-World Risk

While exploiting this vulnerability is not trivial, the potential real-world risk should not be ignored. An attacker with local access to a system performing cryptographic operations using the affected version of curve25519-dalek could potentially recover private keys by carefully analyzing the timing variations in the cryptographic operations. This is particularly concerning for applications where strong cryptographic security is paramount, such as secure communication protocols or digital signature schemes.

Recommendations

• Update to version 4.1.3 or later: The vulnerability has been addressed in version 4.1.3 of the curve25519-dalek crate. Upgrade your dependencies to this version or a later version to mitigate the risk.
• Review your cryptographic implementations: Ensure that your cryptographic implementations are using constant-time operations and are not susceptible to timing side-channel attacks.
• Monitor for suspicious activity: Monitor your systems for any signs of suspicious activity, such as unusual network traffic or attempts to access sensitive data.

Technical Insight

The vulnerability arises because the LLVM compiler incorrectly optimizes away a constant-time operation on elliptic curve scalars within the curve25519-dalek crate. Constant-time operations are designed to ensure that the execution time of an operation does not depend on the value of the input data, thereby preventing timing side-channel attacks. By removing this constant-time operation, the LLVM compiler inadvertently introduces timing variations that can be exploited by attackers to infer information about the private keys used in cryptographic operations. In simpler terms, the compiler "broke" a protection mechanism that was supposed to keep secrets safe by making calculations take a consistent amount of time regardless of what the secret was.

Credit to Researcher(s)

The discovery of this vulnerability is attributed to the security researchers involved in analyzing the curve25519-dalek crate and its interaction with the LLVM compiler.

References

• curve25519-dalek crate
• Pull request addressing the issue
• RustSec Advisory RUSTSEC-2024-0344

Tags

#CVE-2024-58262 #Rust #Cryptography #Side-ChannelAttack #TimingVulnerability #curve25519-dalek

Summary: CVE-2024-58262 exposes a timing side-channel vulnerability in the curve25519-dalek Rust crate. LLVM optimization removes constant-time operations, potentially leaking private key information. Upgrade to version 4.1.3 or later to mitigate the risk.

CVE ID: CVE-2024-58262

Risk Analysis: Successful exploitation can lead to the compromise of sensitive cryptographic keys, potentially undermining the security of applications relying on the curve25519-dalek crate. The impact is primarily confidentiality-related.

Recommendation: Upgrade to curve25519-dalek version 4.1.3 or later to address the vulnerability. Review cryptographic implementations to ensure constant-time operations are not being removed by compiler optimizations.

Timeline

• 2024: Vulnerability introduced in versions prior to 4.1.3
• 2024: Vulnerability discovered and reported
• 2025-07-27: CVE-2024-58262 assigned
• 2025-07-27: Public disclosure

References

• https://crates.io/crates/curve25519-dalek
• https://github.com/dalek-cryptography/curve25519-dalek/pull/659
• https://rustsec.org/advisories/RUSTSEC-2024-0344.html