CVE-2015-7755 — Juniper ScreenOS Improper Authentication Vulnerability

Juniper ScreenOS 6.2.0r15 through 6.2.0r18, 6.3.0r12 before 6.3.0r12b, 6.3.0r13 before 6.3.0r13b, 6.3.0r14 before 6.3.0r14b, 6.3.0r15 before 6.3.0r15b, 6.3.0r16 before 6.3.0r16b, 6.3.0r17 before 6.3.0r17b, 6.3.0r18 before 6.3.0r18b, 6.3.0r19 before 6.3.0r19b, and 6.3.0r20 before

01What is this vulnerability?

Juniper ScreenOS 6.2.0r15 through 6.2.0r18, 6.3.0r12 before 6.3.0r12b, 6.3.0r13 before 6.3.0r13b, 6.3.0r14 before 6.3.0r14b, 6.3.0r15 before 6.3.0r15b, 6.3.0r16 before 6.3.0r16b, 6.3.0r17 before 6.3.0r17b, 6.3.0r18 before 6.3.0r18b, 6.3.0r19 before 6.3.0r19b, and 6.3.0r20 before 6.3.0r21 allows remote attackers to obtain administrative access by entering an unspecified password during a (1) SSH…

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2025-10-02. Ransomware use: Unknown.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2015-12-19T11:00:00.000Z
• Last modified: 2025-10-21T23:55:56.610Z
• Added to CISA KEV: 2025-10-02
• BOD 22-01 due: 2025-10-23

09References

• arstechnica.com — http://arstechnica.com/security/2015/12/unauthorized-code-in-juniper-firewalls-d…
• www.wired.com — http://www.wired.com/2015/12/juniper-networks-hidden-backdoors-show-the-risk-of-…
• www.securitytracker.com — http://www.securitytracker.com/id/1034489
• www.kb.cert.org — http://www.kb.cert.org/vuls/id/640184
• forums.juniper.net — https://forums.juniper.net/t5/Security-Incident-Response/Important-Announcement-…
• github.com — https://github.com/hdm/juniper-cve-2015-7755
• kb.juniper.net — http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10713
• twitter.com — http://twitter.com/cryptoron/statuses/677900647560253442
• adamcaudill.com — https://adamcaudill.com/2015/12/17/much-ado-about-juniper/
• www.forbes.com — http://www.forbes.com/sites/thomasbrewster/2015/12/18/juniper-says-it-didnt-work…
• www.securityfocus.com — http://www.securityfocus.com/bid/79626