Arch Linux Security Advisory ASA-201506-3 ========================================= Severity: High Date : 2015-06-12 CVE-ID : CVE-2015-1788 CVE-2015-1789 CVE-2015-1790 CVE-2015-1791 CVE-2015-1792 CVE-2015-4000 Package : openssl Type : multiple issues Remote : Yes Link : https://wiki.archlinux.org/index.php/CVE Summary ======= The package openssl before version 1.0.2.b-1 is vulnerable to multiple issues including but not limited to man-in-the-middle via cipher downgrade, double free and denial of service. Resolution ========== Upgrade to 1.0.2.b-1. # pacman -Syu "openssl>=1.0.2.b-1" The problems have been fixed upstream in version 1.0.2.b. Workaround ========== None. Description =========== - CVE-2015-1788 (denial of service) When processing an ECParameters structure OpenSSL enters an infinite loop if the curve specified is over a specially malformed binary polynomial field. This can be used to perform denial of service against any system which processes public keys, certificate requests or certificates. This includes TLS clients and TLS servers with client authentication enabled. - CVE-2015-1789 (out-of-bounds read) X509_cmp_time does not properly check the length of the ASN1_TIME string and can read a few bytes out of bounds. In addition, X509_cmp_time accepts an arbitrary number of fractional seconds in the time string. An attacker can use this to craft malformed certificates and CRLs of various sizes and potentially cause a segmentation fault, resulting in a DoS on applications that verify certificates or CRLs. TLS clients that verify CRLs are affected. TLS clients and servers with client authentication enabled may be affected if they use custom verification callbacks. - CVE-2015-1790 (denial of service) The PKCS#7 parsing code does not handle missing inner EncryptedContent correctly. An attacker can craft malformed ASN.1-encoded PKCS#7 blobs with missing content and trigger a NULL pointer dereference on parsing. Applications that decrypt PKCS#7 data or otherwise parse PKCS#7 structures from untrusted sources are affected. OpenSSL clients and servers are not affected. - CVE-2015-1791 (double free) If a NewSessionTicket is received by a multi-threaded client when attempting to reuse a previous ticket then a race condition can occur potentially leading to a double free of the ticket data. - CVE-2015-1792 (denial of service) When verifying a signedData message the CMS code can enter an infinite loop if presented with an unknown hash function OID. This can be used to perform denial of service against any system which verifies signedData messages using the CMS code. - CVE-2015-4000 (cipher downgrade) A vulnerability in the TLS protocol allows a man-in-the-middle attacker to downgrade vulnerable TLS connections using ephemeral Diffie-Hellman key exchange to 512-bit export-grade cryptography. This vulnerability is known as Logjam. OpenSSL has added protection for TLS clients by rejecting handshakes with DH parameters shorter than 768 bits. This limit will be increased to 1024 bits in a future release. Impact ====== A remote attacker is able to perform man-in-the-middle via cipher downgrade, denial of service or possibly have other unspecified impact via various vectors. References ========== https://www.openssl.org/news/secadv_20150611.txt https://access.redhat.com/security/cve/CVE-2015-1788 https://access.redhat.com/security/cve/CVE-2015-1789 https://access.redhat.com/security/cve/CVE-2015-1790 https://access.redhat.com/security/cve/CVE-2015-1791 https://access.redhat.com/security/cve/CVE-2015-1792 https://access.redhat.com/security/cve/CVE-2015-4000