Arch Linux Security Advisory ASA-201601-32 ========================================== Severity: High Date : 2016-01-29 CVE-ID : CVE-2015-3197 CVE-2015-4000 CVE-2016-0701 Package : openssl Type : man-in-the-middle Remote : Yes Link : https://wiki.archlinux.org/index.php/CVE Summary ======= The package openssl before version 1.0.2.f-1 is vulnerable to man-in-the-middle. Resolution ========== Upgrade to 1.0.2.f-1. # pacman -Syu "openssl>=1.0.2.f-1" The problems have been fixed upstream in version 1.0.2.f. Workaround ========== None. Description =========== - CVE-2015-3197 (man-in-the-middle) A flaw was found in the way malicious SSL/TLS clients could negotiate SSLv2 ciphers that have been disabled on the server. This could result in weak SSLv2 ciphers being used for SSL/TLS connections, making them vulnerable to man-in-the-middle attacks. - CVE-2015-4000 (man-in-the-middle) A flaw was found in the way the TLS protocol composes the Diffie-Hellman exchange (for both export and non-export grade cipher suites). An attacker could use this flaw to downgrade a DHE connection to use export-grade key sizes, which could then be broken by sufficient pre-computation. This can lead to a passive man-in-the-middle attack in which the attacker is able to decrypt all traffic. - CVE-2016-0701 (man-in-the-middle) It was found that OpenSSL used weak Diffie-Hellman parameters based on unsafe primes, which were generated and stored in X9.42-style parameter files. An attacker who could force the peer to perform multiple handshakes using the same private DH component could use this flaw to conduct man-in-the-middle attacks on the SSL/TLS connection. Impact ====== A remote attacker is able to perform a man-in-the-middle attack via various vectors. References ========== https://access.redhat.com/security/cve/CVE-2015-3197 https://access.redhat.com/security/cve/CVE-2015-4000 https://access.redhat.com/security/cve/CVE-2016-0701 https://openssl.org/news/secadv/20160128.txt