stunnel before 5.00, when using fork threading, does not properly update the state of the OpenSSL pseudo-random number generator (PRNG), which causes subsequent children with the same process ID to use the same entropy pool and allows remote attackers to obtain private keys for EC (ECDSA) or DSA certificates.

Updated stunnel package fixes security vulnerability :

A flaw was found in the way stunnel, a socket wrapper which can provide SSL support to ordinary applications, performed (re)initialization of PRNG after fork. When accepting a new connection, the server forks and the child process handles the request. The RAND_bytes() function of openssl doesn't reset its state after the fork, but seeds the PRNG with the output of time(NULL). The most important consequence is that servers using EC (ECDSA) or DSA certificates may under certain conditions leak their private key (CVE-2014-0016).

The updated packages fix this issue by using threads instead of new processes to handle connections.

Also an issue has been corrected where the directory for the pid file was not being created when the package is installed.

An issue currently exists in Mageia 4 where it fails trying to use FIPS SSL (mga#13124). This can be worked around by adding fips = no into the config.

The remote host is affected by the vulnerability described in GLSA-201408-14 (stunnel: Information disclosure)

    stunnel does not properly update the state of the pseudo-random       generator after fork-threading which causes subsequent children with the       same process ID to use the same entropy pool. ECDSA and DSA keys, when       not used in deterministic mode (RFC6979), rely on random data for its k       parameter to not leak private key information.
  Impact :

    A remote attacker may gain access to private key information from ECDSA       or DSA keys.
  Workaround :

    There is no known workaround at this time.

The version of stunnel installed on the remote host is prior to version 5.00. It is, therefore, affected by a security weakness due to the PRNG state not being reset for new connections where the server forks. A remote attacker can exploit this issue to disclose sensitive information, such as the private key used for EC (ECDSA) or DSA certificates.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.

ID	Name	Product	Family	Severity
82349	Mandriva Linux Security Advisory : stunnel (MDVSA-2015:096)	Nessus	Mandriva Local Security Checks	medium
77458	GLSA-201408-14 : stunnel: Information disclosure	Nessus	Gentoo Local Security Checks	medium
73212	stunnel < 5.00 PRNG State Security Weakness	Nessus	Windows	medium

Detections

Analytics

CVE-2014-0016

high

Tenable Plugins

medium

medium

medium