CVE-2026-57082— Net::BitTorrent versions through 2.0.1 for Perl generate the MSE Diffie-Hellman private key with a non-cryptographic PRNG

Net::BitTorrent versions through 2.0.1 for Perl generate the MSE Diffie-Hellman private key with a non-cryptographic PRNG

Net::BitTorrent versions through 2.0.1 for Perl generate the MSE Diffie-Hellman private key with a non-cryptographic PRNG. The MSE (Message Stream Encryption) handshake derives its 160-bit Diffie-Hellman private key from Perl's rand(), a non-cryptographic drand48-class generator seeded once per process, in KeyExchange.pm. The shared secret and the RC4 keys derived from it (the SHA-1 of "keyA" or "keyB", the shared secret, and the infohash) therefore depend entirely on a predictable PRNG. The same handshake sends, in cleartext, random padding drawn from the same rand() sequence in _random_pad, immediately after the public key and the private-key draw. A passive observer of the handshake recovers the PRNG state from the cleartext padding, reconstructs the private key, computes the shared secret from the peer's public key on the wire, derives the RC4 keys, and decrypts the connection, defeating the passive-observation obfuscation MSE provides.

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使用具有密码学弱点缺陷的PRNG

Sanko Robinson Net::BitTorrent 加密问题漏洞

Sanko Robinson Net::BitTorrent是Sanko Robinson个人开发者的一个基于现代 Perl（v5.40+）从头重写的高性能 BitTorrent 客户端库，支持 BitTorrent v2、DHT、协议加密等完整功能，且可与任意事件循环集成。 Sanko Robinson Net::BitTorrent 2.0.1及之前版本存在加密问题漏洞，该漏洞源于在KeyExchange.pm中使用非加密PRNG生成MSE Diffie-Hellman私钥，可能导致被动观察者恢复PR

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