It was found that in the OpenSSL address implementation the hard coded 1024 bit DH p parameter was not prime. The effective cryptographic strength of a key exchange using these parameters was weaker than the one one could get by using a prime p, making easier for eavesdropper to recover the shared secret from a key exchange that uses them. Affected versions are 1.7.3.0 and 2.0.0-b8. CVE request: http://seclists.org/oss-sec/2016/q1/261
why was this closed again? It is a real bug for which there is a bug fix
(In reply to Paul Wouters from comment #1) > why was this closed again? It is a real bug for which there is a bug fix Versions we ship are listed in advisory as not affected.
Upstream commit: http://repo.or.cz/socat.git/commitdiff/eab3c89f2dc0df0d9638941891e8ab233dfb0611 The problematic 1024 bit DH param was introduced in this commit in version 1.7.3.0: http://repo.or.cz/socat.git/commitdiff/281d1bd6515c2f0f8984fc168fb3d3b91c20bdc0 socat versions in Red Hat Enterprise Linux 7 and Fedora / EPEL are all 1.7.2.x, and hence use 512 bit DH params by default. Of course, such short parameters are known to be too weak these days - see LOGJAM / bug 1223211 - and should be replaced. We've had Red Hat Enterprise Linux 7 bug 1021946 open for that for a while now. Users of socat can use dhparams or cert options for OPENSSL address type to make it use custom stronger DH parameters. Upstream security advisory link follows. External References: http://www.dest-unreach.org/socat/contrib/socat-secadv7.html