Multiple traffic classification vulnerabilities in Juniper Networks Junos OS on the SRX Series Services Gateways may allow an attacker to bypass Juniper Deep Packet Inspection (JDPI) rules and access unauthorized networks or resources, when ' no-syn-check' is enabled on the device. In one case, JDPI incorrectly classifies out-of-state asymmetric TCP flows as the dynamic-application INCONCLUSIVE instead of UNKNOWN, which is more permissive. A second issue was discovered where the dynamic-application classification is not properly provided to the policy module and hence traffic continues to use the pre-id-default-policy. In both cases, without the combination of fixes, the firewall allows traffic to be forwarded that should have been denied. causing the firewall to allow traffic to be forwarded that should have been denied.

These issues only occur when ' set security flow tcp-session no-syn-check ' is configured on the device.

One or more of these issues affect Juniper Networks Junos OS on SRX Series:

• 18.4 versions prior to 18.4R2-S10, 18.4R3-S10;
• 19.1 versions prior to 19.1R3-S8;
• 19.2 versions prior to 19.2R1-S8, 19.2R3-S4;
• 19.3 versions prior to 19.3R3-S3;
• 19.4 versions prior to 19.4R3-S5;
• 20.1 versions prior to 20.1R3-S1;
• 20.2 versions prior to 20.2R3-S2;
• 20.3 versions prior to 20.3R3-S1;
• 20.4 versions prior to 20.4R2-S2, 20.4R3;
• 21.1 versions prior to 21.1R2-S2, 21.1R3;
• 21.2 versions prior to 21.2R2.

These issues do not affect Juniper Networks Junos OS versions prior to 18.4R1.

These issues will only be seen when the following configuration is present:

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

These issues were seen during production usage.

The following issues have been reported and resolved:

The following software releases have been updated to resolve both issues: Junos OS 18.4R2-S10, 18.4R3-S10, 19.1R3-S8, 19.2R1-S8, 19.2R3-S4, 19.3R3-S3, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 20.4R2-S2, 20.4R3, 21.1R2-S2, 21.1R3, 21.2R2, 21.3R1, and all subsequent releases.

Notes:

1. The original issue was first introduced in Junos OS 18.4R1.
    
2. PR 1561533 was resolved in Junos OS 18.4R2-S9, 18.4R3-S9, 19.1R2-S3, 19.1R3-S6, 19.2R1-S7, 19.2R3-S3, 19.3R2-S6, 19.3R3-S2, 19.4R2-S5, 19.4R3-S3, 20.1R2-S2, 20.1R3, 20.2R3-S1, 20.3R3, 20.4R2-S1, 20.4R3, 21.1R1-S1, 21.1R2, 21.2R1
    
3. PR 1599053 was resolved in Junos OS 18.4R2-S10, 18.4R3-S10, 19.1R3-S8, 19.2R1-S8, 19.2R3-S4, 19.3R3-S3, 19.4R3-S5, 20.1R3-S1, 20.2R3-S2, 20.3R3-S1, 20.4R2-S2, 20.4R3, 21.1R2-S2, 21.1R3, 21.2R2, 21.3R1, 21.4R1

Both PRs are resolved in the releases listed above.

These issues are being tracked as  1561533  and  1599053 .
 

Software releases or updates are available for download at https://support.juniper.net/support/downloads/
 

Either of the following workarounds will mitigate these issues:

1. Remove ' security flow tcp-session no-syn-check ' from the configuration.
2. Enable AppID cache configuration:
   set services application-identification application-system-cache security-services

• KB16613: Overview of the Juniper Networks SIRT Quarterly Security Bulletin Publication Process [juniper.net]
• KB16765: In which releases are vulnerabilities fixed? [juniper.net]
• KB16446: Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories [juniper.net]
• Report a Security Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2022-22157 at cve.mitre.org
• CVE-2022-22167 at cve.org