Product Affected

This issue can affect all SRX Series services gateways configured with a security-zone screen to limit access to host inbound traffic.
Medium
6.8 (AV:N/AC:L/Au:S/C:C/I:N/A:N)

Problem


Inbound "to-self" management traffic (eg. ssh, telnet, ping, etc.) is accepted by the device even though the service is not explicitly included in the 'host-inbound-traffic' configuration for the ingress interface within the security-zone. For example: 
security-zone UNTRUSTED {
    address-book {
        address fafc-10.203.150.126/32 10.203.150.126/32;
        address host-10.6.145.232 10.6.145.232/32;
    }
    screen untrusted-screen;
    interfaces {
        reth1.10 {
            host-inbound-traffic {
                system-services {
                    traceroute;
                    ping;
                }
            }
        }
    }
}
In the sample configuration above, only traceroute and ping should be allowed, but SSH is also allowed on the interface.

The issue only occurs if the destination IP address exists on another interface on a different VR.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

No other Juniper Networks products or platforms are affected by this issue.

Solution


The destined interface was not correctly identified due to an incorrect destination route-table ID. After performing a routing lookup, even though the packet is routed to-self, the flow handled it like a pass-through packet, which is normally permitted by the default to-self policy.

All Junos OS software releases built on or after 2012-06-21 have fixed this specific issue. Releases containing the fix specifically include: 10.4R10, 11.2R7, 11.4R4, 12.1R2-S1, 12.1R3 and all subsequent releases (i.e. all releases built after 12.1R3).

This issue is being tracked as PR 754392 and is visible on the Customer Support website.

KB16765 [juniper.net] - "In which releases are vulnerabilities fixed?" describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.


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.

Workaround


No known workaround exists for this issue.

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

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