CVE-2021-43398 : Security Advisory and Response

Crypto++ (aka Cryptopp) 8.6.0 and earlier versions contain a timing leakage vulnerability in MakePublicKey(), potentially leading to information disclosure through timing attacks.

Understanding CVE-2021-43398

What is CVE-2021-43398?

Crypto++ (aka Cryptopp) 8.6.0 and earlier versions have a timing leakage vulnerability in MakePublicKey(), causing a correlation between execution time and private key length, which could expose private key information to attackers.

The Impact of CVE-2021-43398

The vulnerability may enable attackers to carry out timing attacks and obtain private key length information, compromising the security of the system. However, the report is disputed by the vendor and other third parties who claim that the differences in execution time are intentional, aiming at user choice between strength and performance.

Technical Details of CVE-2021-43398

Vulnerability Description

Crypto++ 8.6.0 and earlier versions suffer from a timing leakage vulnerability in MakePublicKey(), resulting in a clear relationship between execution time and private key length.

Affected Systems and Versions

Product: Crypto++ (aka Cryptopp)
Vendor: n/a
Versions: 8.6.0 and earlier

Exploitation Mechanism

The timing leakage in MakePublicKey() may allow attackers to conduct timing attacks by correlating execution time with private key length, potentially leading to disclosure of sensitive information.

Mitigation and Prevention

Immediate Steps to Take

Monitor for any unusual timing patterns or delays in key generation processes.
Implement randomization to mitigate timing side-channel attacks.
Stay informed about vendor updates and security advisories.

Long-Term Security Practices

Regularly review and update cryptographic libraries.
Conduct security assessments focusing on timing vulnerabilities.

Patching and Updates

Apply security patches provided by the vendor to address the timing leakage issue in MakePublicKey().