On SRX Series and MX Series devices with a Service PIC with any ALG enabled, a crafted TCP/IP response packet processed through the device results in memory corruption leading to one or more daemon(s) crashing. Sustained crafted response packets lead to repeated crashes of affected daemon(s) which results in an extended Denial of Service condition.

Affected releases are Juniper Networks Junos OS:

• 12.1X46 versions prior to 12.1X46-D60 on SRX series;
• 12.3X48 versions prior to 12.3X48-D35 on SRX series;
• 14.1 versions prior to 14.1R9 on MX series;
• 14.2 versions prior to 14.2R8 on MX series;
• 15.1X49 versions prior to 15.1X49-D60 on SRX series;
• 15.1 versions prior to 15.1R5-S8, 15.1F6-S9, 15.1R6-S4, 15.1R7 on MX series;
• 16.1 versions prior to 16.1R6 on MX series;
• 16.2 versions prior to 16.2R3 on MX series;
• 17.1 versions prior to 17.1R2-S4, 17.1R3 on MX series.

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

This issue affects any enabled IPv4 ALG.

This issue only affects IPv4.  This issue does not affect IPv6.

This issue affects unicast traffic only.

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

This issue was seen in a production network.

This issue has been assigned CVE-2018-0002 .

The following software releases have been updated to resolve this specific issue: 12.1X46-D60, 12.3X48-D35, 14.1R9, 14.2R8, 15.1X49-D60, 15.1R5-S8, 15.1R6-S4, 15.1F6-S9, 15.1R7, 16.1R6, 16.2R3, 17.1R2-S4, 17.1R3, 17.2R1 and all subsequent releases.

This issue is being tracked as 1183181 which is visible on the Customer Support website.

Note: Juniper SIRT's policy is not to evaluate releases which are beyond End of Engineering (EOE) or End of Life (EOL).

Software Releases, patches and updates are available at https://www.juniper.net/support/downloads/ .

Disable IPv4 ALG's on affected devices.

2018-01-10: Initial publication
2018-02-05: Removed flowd language and homogenized language as more than one process may be impacted on different platforms.

• 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 Vulnerability - How to Contact the Juniper Networks Security Incident Response Team
• CVE-2018-0002: MX series, SRX series: Junos OS: Denial of service vulnerability in Flowd on devices with ALG enabled.