Vulnerabilities > CVE-2019-3685 - Improper Certificate Validation vulnerability in Opensuse Open Build Service
Attack vector
NETWORK Attack complexity
HIGH Privileges required
NONE Confidentiality impact
HIGH Integrity impact
HIGH Availability impact
LOW Summary
Open Build Service before version 0.165.4 diddn't validate TLS certificates for HTTPS connections with the osc client binary
Vulnerable Configurations
Common Weakness Enumeration (CWE)
Common Attack Pattern Enumeration and Classification (CAPEC)
- Creating a Rogue Certificate Authority Certificate An attacker exploits a weakness in the MD5 hash algorithm (weak collision resistance) to generate a certificate signing request (CSR) that contains collision blocks in the "to be signed" part. The attacker specially crafts two different, but valid X.509 certificates that when hashed with the MD5 algorithm would yield the same value. The attacker then sends the CSR for one of the certificates to the Certification Authority which uses the MD5 hashing algorithm. That request is completely valid and the Certificate Authority issues an X.509 certificate to the attacker which is signed with its private key. An attacker then takes that signed blob and inserts it into another X.509 certificate that the attacker generated. Due to the MD5 collision, both certificates, though different, hash to the same value and so the signed blob works just as well in the second certificate. The net effect is that the attackers' second X.509 certificate, which the Certification Authority has never seen, is now signed and validated by that Certification Authority. To make the attack more interesting, the second certificate could be not just a regular certificate, but rather itself a signing certificate. Thus the attacker is able to start their own Certification Authority that is anchored in its root of trust in the legitimate Certification Authority that has signed the attackers' first X.509 certificate. If the original Certificate Authority was accepted by default by browsers, so will now the Certificate Authority set up by the attacker and of course any certificates that it signs. So the attacker is now able to generate any SSL certificates to impersonate any web server, and the user's browser will not issue any warning to the victim. This can be used to compromise HTTPS communications and other types of systems where PKI and X.509 certificates may be used (e.g., VPN, IPSec) .
Nessus
| NASL family | SuSE Local Security Checks |
| NASL id | OPENSUSE-2019-1844.NASL |
| description | This update for osc to version 0.165.4 fixes the following issues : Security issue fixed : - CVE-2019-3685: Fixed broken TLS certificate handling allowing for a Man-in-the-middle attack (bsc#1142518). Non-security issues fixed : - support different token operations (runservice, release and rebuild) (requires OBS 2.10) - fix osc token decode error - offline build mode is now really offline and does not try to download the buildconfig - osc build -define now works with python3 - fixes an issue where the error message on osc meta -e was not parsed correctly - osc maintainer -s now works with python3 - simplified and fixed osc meta -e (bsc#1138977) - osc lbl now works with non utf8 encoding (bsc#1129889) - add simpleimage as local build type - allow optional fork when creating a maintenance request - fix RPMError fallback - fix local caching for all package formats - fix appname for trusted cert store - osc -h does not break anymore when using plugins - switch to difflib.diff_bytes and sys.stdout.buffer.write for diffing. This will fix all decoding issues with osc diff, osc ci and osc rq -d - fix osc ls -lb handling empty size and mtime - removed decoding on osc api command. This update was imported from the SUSE:SLE-15-SP1:Update update project. |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 127833 |
| published | 2019-08-13 |
| reporter | This script is Copyright (C) 2019-2020 and is owned by Tenable, Inc. or an Affiliate thereof. |
| source | https://www.tenable.com/plugins/nessus/127833 |
| title | openSUSE Security Update : osc (openSUSE-2019-1844) |
| code | |