An unauthenticated root login may allow upon reboot when a commit script is used. A commit script allows a device administrator to execute certain instructions during commit, which is configured under the [system scripts commit] stanza. Certain commit scripts that work without a problem during normal commit may cause unexpected behavior upon reboot which can leave the system in a state where root CLI login is allowed without a password due to the system reverting to a "safe mode" authentication state. Lastly, only logging in physically to the console port as root, with no password, will work.

Affected releases are Juniper Networks Junos OS:

• 12.1X46 versions prior to 12.1X46-D71 on SRX;
• 12.3X48 versions prior to 12.3X48-D55 on SRX;
• 14.1 versions prior to 14.1R9;
• 14.1X53 versions prior to 14.1X53-D40 on QFX, EX;
• 14.2 versions prior to 14.2R7-S9, 14.2R8;
• 15.1 versions prior to 15.1F5-S7, 15.1F6-S8, 15.1R5-S6, 15.1R6;
• 15.1X49 versions prior to 15.1X49-D110 on SRX;
• 15.1X53 versions prior to 15.1X53-D232 on QFX5200/5110;
• 15.1X53 versions prior to 15.1X53-D49, 15.1X53-D470 on NFX;
• 15.1X53 versions prior to 15.1X53-D59 on EX2300/EX3400
• 15.1X53 versions prior to 15.1X53-D65 on QFX10K;
• 16.1 versions prior to 16.1R2.

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

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-2018-0008 .

The following software releases have been updated to resolve this specific issue: 12.1X46-D71, 12.3X48-D55, 14.1R9, 14.1X53-D40, 14.2R7-S9, 14.2R8, 15.1F5-S7, 15.1F6-S8, 15.1R5-S6, 15.1R6, 15.1X49-D110, 15.1X53-D49, 15.1X53-D59, 15.1X53-D470, 15.1X53-D232, 15.1X53-D65, 16.1R2, 16.2R1 and all subsequent releases.

This issue is being tracked as 1179601 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/ .

While there is no published workaround exists for this issue, customer can verify whether their commit script contains the affected configuration by rebooting the device. Please contact JTAC if after the reboot the device enters a state where root CLI login is allowed without a password.

2018-01-10: Initial publication
2018-02-27: updating solution info on EX2300/EX3400

• 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-2018-0008: Junos OS: commit script may allow unauthenticated root login upon reboot