Arch Linux Security Advisory ASA-201804-2 ========================================= Severity: Medium Date : 2018-04-01 CVE-ID : CVE-2017-3738 CVE-2018-0739 Package : openssl Type : multiple issues Remote : Yes Link : https://security.archlinux.org/AVG-540 Summary ======= The package openssl before version 1.1.0.h-1 is vulnerable to multiple issues including denial of service and private key recovery. Resolution ========== Upgrade to 1.1.0.h-1. # pacman -Syu "openssl>=1.1.0.h-1" The problems have been fixed upstream in version 1.1.0.h. Workaround ========== None. Description =========== - CVE-2017-3738 (private key recovery) There is an overflow bug in the AVX2 Montgomery multiplication procedure used in exponentiation with 1024-bit moduli. No EC algorithms are affected. Analysis suggests that attacks against RSA and DSA as a result of this defect would be very difficult to perform and are not believed likely. Attacks against DH1024 are considered just feasible, because most of the work necessary to deduce information about a private key may be performed offline. The amount of resources required for such an attack would be significant. However, for an attack on TLS to be meaningful, the server would have to share the DH1024 private key among multiple clients, which is no longer an option since CVE-2016-0701. - CVE-2018-0739 (denial of service) A stack-exhaustion issue has been found in OpenSSL <= 1.1.0h, where constructed ASN.1 types with a recursive definition (such as can be found in PKCS7) could eventually exceed the stack given malicious input with excessive recursion. This could result in a Denial Of Service attack. There are no such structures used within SSL/TLS that come from untrusted sources so this is considered safe. Impact ====== A remote attacker might be able to recover a private key (in very unlikely cases), or cause a denial of service by providing a crafted ASN.1 type to a vulnerable application. References ========== https://www.openssl.org/news/vulnerabilities.html#2017-3738 https://www.openssl.org/news/secadv/20171207.txt https://github.com/openssl/openssl/commit/5630661aecbea5fe3c4740f5fea744a1f0... https://www.openssl.org/news/secadv/20180327.txt https://github.com/openssl/openssl/commit/2ac4c6f7b2b2af20c0e2b0ba05367e454c... https://security.archlinux.org/CVE-2017-3738 https://security.archlinux.org/CVE-2018-0739