2016-07 Security Bulletin: Junos: Self-signed certificate with spoofed trusted Issuer CN accepted as valid (CVE-2016-1280)Product Affected:This issue can affect any product or platform running Junos OS
Problem:Junos OS runs PKId for certificate validation. When a peer device presents a self-signed certificate as its end entity certificate with its issuer name matching one of the valid CA certificates enrolled in Junos, the peer certificate validation is skipped and the peer certificate is treated as valid. This may allow an attacker to generate a specially crafted self-signed certificate and bypass certificate validation.This issue only affects certificates used for IKE/IPsec.  Other public key-based authentication is unaffected by this vulnerability.Juniper SIRT is not aware of any malicious exploitation of this vulnerability.No other Juniper Networks products or platforms are affected by this issue.This issue has been assigned CVE-2016-1280.
Solution:The following software releases have been updated to resolve this specific issue: Junos OS 12.1X44-D52, 12.1X44-D55, 12.1X46-D37, 12.1X46-D40, 12.1X47-D30, 12.3R12, 12.3X48-D20, 13.3R10, 14.1R8, 14.1X53-D40*, 14.2R7, 15.1R4, 15.1X49-D20, 15.1X53-D60*, 16.1R1, and all subsequent releases.*Available Q3/2016This issue is being tracked as PR 1096758 and is visible on the Customer Support website.KB16765 – “In which releases are vulnerabilities fixed?” describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.
Workaround:Configure all PKI-VPN tunnels to accept only Distinguished Name (DN) as the remote peer’s IKE ID.Example for SRX devices:The SRX can match the DN by exact string, or a wildcard string. If a wildcard string is used, it must not match any of its trusted CA’s Subject name.One of the following four options can be used:

set security ike gateway <peer name> dynamic distinguished-name container <peer certificate’s subject string>
set security ike gateway <peer name> dynamic distinguished-name wildcard <wildcard string>
set security ike gateway <peer name> remote-identity distinguished-name container <peer certificate’s subject string>
set security ike gateway <peer name> remote-identity distinguished-name wildcard <wildcard string>

Note: The remote peer’s tunnel must also be reconfigured to identify itself using its DN as the IKE ID. For SRX devices, the config statement is:

set security ike gateway <peer name> local-identity distinguished-name

Implementation:How to obtain fixed software:Security vulnerabilities in Junos are fixed in the next available Maintenance Release of each supported Junos version. In some cases, a Maintenance Release is not planned to be available in an appropriate time-frame. For these cases, Service Releases are made available in order to be more timely. Security Advisory and Security Notices will indicate which Maintenance and Service Releases contain fixes for the issues described. Upon request to JTAC, customers will be provided download instructions for a Service Release. Although Juniper does not provide formal Release Note documentation for a Service Release, a list of “PRs fixed” can be provided on request.Modification History:
2016-07-13: Initial publication2016-07-15: Removed mitigation of disallowing usage of self-signed certificates for IKE/IPsec authentication

Related Links:CVSS Score:6.5 (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)
Risk Level:Medium
Risk Assessment:Information for how Juniper Networks uses CVSS can be found at KB 16446 “Common Vulnerability Scoring System (CVSS) and Juniper’s Security Advisories.”

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