Vulnerabilities > CVE-2017-10620 - Improper Certificate Validation vulnerability in Juniper Junos 12.1X46/12.3X48/15.1X49
Attack vector
NETWORK Attack complexity
HIGH Privileges required
NONE Confidentiality impact
NONE Integrity impact
HIGH Availability impact
HIGH Summary
Juniper Networks Junos OS on SRX series devices do not verify the HTTPS server certificate before downloading anti-virus updates. This may allow a man-in-the-middle attacker to inject bogus signatures to cause service disruptions or make the device not detect certain types of attacks. Affected Junos OS releases are: 12.1X46 prior to 12.1X46-D71; 12.3X48 prior to 12.3X48-D55; 15.1X49 prior to 15.1X49-D110;
Vulnerable Configurations
| Part | Description | Count |
|---|---|---|
| OS | 40 | |
| Hardware | Juniper
| 20 |
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 | Junos Local Security Checks |
| NASL id | JUNIPER_JSA10822.NASL |
| description | According to its self-reported version number, the remote Junos device is affected by a vulnerability in that the HTTPS server certificate is not verified before downloading anti-virus updates. |
| last seen | 2020-06-01 |
| modified | 2020-06-02 |
| plugin id | 104041 |
| published | 2017-10-20 |
| reporter | This script is Copyright (C) 2017-2018 Tenable Network Security, Inc. |
| source | https://www.tenable.com/plugins/nessus/104041 |
| title | Juniper Junos HTTPS Server Certificate AV Vulnerability (JSA10822) |
| code | |