جزئیات آسیب‌پذیری

Crypt::DSA versions before 1.22 for Perl draw the DSA signing nonce and private key from a biased random generator, leading to private-key recovery. "Crypt::DSA::Util::makerandom forces the high bit of every value it returns to obtain an exactly N-bit integer for prime search. The signing nonce and the private key are drawn from makerandom. Because the high bit is always set, the result is not uniform: its top bit is fixed, producing insecure values." An attacker who collects a modest number of signatures under an affected key, together with the public key, can recover the private key with a lattice attack. Keys used to sign with an affected version should be considered compromised and new keys should be generated.

• https://metacpan.org/release/TIMLEGGE/Crypt-DSA-1.21/source/lib/Crypt/DSA/Util.pm#L56
• https://metacpan.org/release/TIMLEGGE/Crypt-DSA-1.22/diff/TIMLEGGE/Crypt-DSA-1.21#lib/Crypt/DSA/Util.pm
• https://metacpan.org/release/TIMLEGGE/Crypt-DSA-1.22/changes release-notes
• http://www.openwall.com/lists/oss-security/2026/07/05/1