/ 
Authen-SASL-2.10
/ Authen::SASL::Perl::DIGEST_MD5
Security Advisories (2)
CVE-2025-40918 (2025-07-16)

Authen::SASL::Perl::DIGEST_MD5 versions 2.04 through 2.1800 for Perl generates the cnonce insecurely. The cnonce (client nonce) is generated from an MD5 hash of the PID, the epoch time and the built-in rand function. The PID will come from a small set of numbers, and the epoch time may be guessed, if it is not leaked from the HTTP Date header. The built-in rand function is unsuitable for cryptographic usage. According to RFC 2831, The cnonce-value is an opaque quoted string value provided by the client and used by both client and server to avoid chosen plaintext attacks, and to provide mutual authentication. The security of the implementation depends on a good choice. It is RECOMMENDED that it contain at least 64 bits of entropy.

CVE-2026-86219 (2026-09-06)

Authen::SASL::Perl::DIGEST_MD5 versions before 2.2100 for Perl accept replayed authentication responses via unverified nonce in server_step. server_start generates a fresh nonce and sends it in the challenge, and nothing later compares that value against the nonce the client returns. server_step derives the expected digest from the client's own parameters, so a response verifies whenever its digest matches the nonce it carries. The count table it also checks is keyed on the client-supplied nonce and starts empty in each new server object, so a captured first response, carrying `nc=00000001`, passes that too. RFC 2831 defines the nonce in the response as the value the server sent in the preceding challenge. An attacker who observes one successful `qop=auth` exchange can replay the captured response against a later session for the same service, host, realm and user, and authenticate as that user without knowing the password.

NAME

Authen::SASL::Perl::DIGEST_MD5 - Digest MD5 Authentication class

SYNOPSIS

use Authen::SASL qw(Perl);

$sasl = Authen::SASL->new(
  mechanism => 'DIGEST-MD5',
  callback  => {
    user => $user, 
    pass => $pass,
    serv => $serv
  },
);

DESCRIPTION

This method implements the client part of the DIGEST-MD5 SASL algorithm, as described in RFC-2831.

This module only implements the auth operation which offers authentication but neither integrity protection not encryption.

CALLBACK

The callbacks used are:

authname

The authorization id to use after successful authentication

user

The username to be used in the response

pass

The password to be used in the response

serv

The service name when authenticating to a replicated service

realm

The authentication realm when overriding the server-provided default. If not given the server-provided value is used.

The callback will be passed the list of realms that the server provided in the initial response.

SEE ALSO

Authen::SASL, Authen::SASL::Perl

AUTHORS

Graham Barr, Djamel Boudjerda (NEXOR), Paul Connolly, Julian Onions (NEXOR)

Please report any bugs, or post any suggestions, to the perl-ldap mailing list <perl-ldap@perl.org>

COPYRIGHT

Copyright (c) 2003-2005 Graham Barr, Djamel Boudjerda, Paul Connolly, Julian Onions, Nexor and Peter Marschall. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.