CVE-2018-20187 : Vulnerability Insights and Analysis

Botan, prior to version 2.9.0, has a side-channel vulnerability that could allow an attacker to gain insight into the upper bits of a secret key during ECC key generation.

Understanding CVE-2018-20187

What is CVE-2018-20187?

Botan, a cryptographic library, is vulnerable to a side-channel attack during ECC key generation, potentially exposing secret key information.

The Impact of CVE-2018-20187

The vulnerability affects the key generation process in Botan but does not impact ECDSA signatures or ECDH key agreement.

Technical Details of CVE-2018-20187

Vulnerability Description

Botan before version 2.9.0 is susceptible to a side-channel issue during ECC key generation.
An attacker measuring the time for key generation may infer high bits of the secret key.

Affected Systems and Versions

Product: Not applicable
Vendor: Not applicable
Versions affected: Not applicable

Exploitation Mechanism

The vulnerability arises from the unblinded Montgomery ladder used in deriving the public point from the secret scalar.
The loop iteration count adjusts based on the secret's bitlength, potentially leaking key information.

Mitigation and Prevention

Immediate Steps to Take

Upgrade Botan to version 2.9.0 or newer to mitigate the side-channel vulnerability.
Implement secure key generation practices to minimize the risk of side-channel attacks.

Long-Term Security Practices

Regularly monitor for security updates and patches from Botan.
Conduct security assessments to identify and address potential vulnerabilities in cryptographic operations.

Patching and Updates

Stay informed about security advisories and updates from Botan to promptly apply patches and protect against known vulnerabilities.