Vulnerability DatabaseCVE-2020-35926

CVE-2020-35926:
Rust vulnerability analysis and mitigation

Overview

An issue was discovered in the nanorand crate before version 0.5.1 for Rust, affecting its random number generator (RNG) implementation. The vulnerability caused any RNG implementation, including the cryptographically secure ChaCha generator, to return all zeroes due to improper integer truncation handling (RustSec Advisory, NVD).

Technical details

The vulnerability stemmed from using bit-shifting operations to truncate 64-bit numbers instead of using proper type conversion for standard unsigned integers. This implementation error in the RandomGen implementations resulted in the RNG consistently returning zero values, affecting all random number generation including cryptographically secure operations. The issue has been assigned a CVSS v3.1 base score of 9.8 (CRITICAL) with vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (NVD).

Impact

The vulnerability compromised the effectiveness of all random number generation in affected versions, causing predictable (all zero) outputs instead of random values. This had significant implications for any security-critical applications relying on nanorand for randomization, particularly those using the ChaCha cryptographic RNG (RustSec Advisory).

Mitigation and workarounds

The issue has been fixed in nanorand version 0.5.1 and later releases. Users should upgrade to version 0.5.1 or newer to resolve the vulnerability. No alternative workarounds are available for affected versions (RustSec Advisory).

Community reactions

The vulnerability was initially disclosed on Twitter by the developer, highlighting the critical nature of the bug and its impact on random number generation (RustSec Advisory).