VDB-79855 · CVE-2015-7755 · JSA10713

Juniper ScreenOS up to 6.2.0r18/6.3.0r20 SSH/Telnet Username improper authentication

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.7	$0-$5k	0.00

Summaryinfo

A vulnerability classified as critical has been found in Juniper ScreenOS up to 6.2.0r18/6.3.0r20. The affected element is an unknown function of the component SSH/Telnet. This manipulation of the argument Username with the input username1/username2 causes improper authentication. This vulnerability is registered as CVE-2015-7755. Furthermore, an exploit is available. It is recommended to upgrade the affected component.

Detailsinfo

A vulnerability was found in Juniper ScreenOS up to 6.2.0r18/6.3.0r20 (Router Operating System). It has been declared as critical. Affected by this vulnerability is some unknown processing of the component SSH/Telnet. The manipulation of the argument Username with the input value username1/username2 leads to a improper authentication vulnerability. The CWE definition for the vulnerability is CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was published 12/17/2015 as JSA10713 as confirmed advisory (Website). It is possible to read the advisory at kb.juniper.net. This vulnerability is known as CVE-2015-7755 since 10/08/2015. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details and also a public exploit are known. The advisory points out:

During an internal code review, two security issues were identified. The first issue allows unauthorized remote administrative access to the device over SSH or telnet. Exploitation of this vulnerability can lead to complete compromise of the affected system.

After immediately, there has been an exploit disclosed. It is possible to download the exploit at kb.juniper.net. It is declared as attacked. We expect the 0-day to have been worth approximately $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 87507 (Juniper ScreenOS 6.2.x < 6.2.0r19 / 6.3.x < 6.3.0r21 Multiple Vulnerabilities (JSA10713)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Firewalls and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 38259 (SSH User Login Bruteforced). The CISA Known Exploited Vulnerabilities Catalog lists this issue since 10/02/2025 with a due date of 10/23/2025:

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Upgrading to version 6.2.0r19 or 6.3.0r21 eliminates this vulnerability. A possible mitigation has been published immediately after the disclosure of the vulnerability. The advisory contains the following remark:

Upon exploitation of this vulnerability, the log file would contain an entry that ‘system’ had logged on followed by password authentication for a username.

The vulnerability is also documented in the databases at Zero-Day.cz (265), Tenable (87507), SecurityFocus (BID 79626†) and SecurityTracker (ID 1034489†). Similar entries are available at VDB-14087, VDB-79856 and VDB-79874. Be aware that VulDB is the high quality source for vulnerability data.

Productinfo

Type

Router Operating System

Vendor

Juniper

Name

ScreenOS

Version

License

commercial

Website

Vendor: https://www.juniper.net/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.8
VulDB Meta Temp Score: 9.7

VulDB Base Score: 9.8
VulDB Temp Score: 9.4
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍

ADP CISA Base Score: 9.8
ADP CISA Vector: 🔍

CVSSv2info

AV	AC	Au	C	I	A
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Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
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Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Improper authentication
CWE: CWE-287
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Attacked
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

KEV Added: 🔍
KEV Due: 🔍
KEV Remediation: 🔍
KEV Ransomware: 🔍
KEV Notice: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Nessus ID: 87507
Nessus Name: Juniper ScreenOS 6.2.x < 6.2.0r19 / 6.3.x < 6.3.0r21 Multiple Vulnerabilities (JSA10713)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 802738
OpenVAS Name: Backdoor in ScreenOS
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

MetaSploit ID: juniper_backdoor.rb
MetaSploit Name: Juniper SSH Backdoor Scanner
MetaSploit File: 🔍

Zero-Day.cz: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Upgrade: ScreenOS 6.2.0r19/6.3.0r21
Suricata ID: 2022291
Suricata Class: 🔍
Suricata Message: 🔍

Timelineinfo

10/08/2015 🔍
12/17/2015 +70 days 🔍
12/17/2015 +0 days 🔍
12/17/2015 +0 days 🔍
12/18/2015 +1 days 🔍
12/18/2015 +0 days 🔍
12/18/2015 +0 days 🔍
12/19/2015 +1 days 🔍
04/23/2026 +3777 days 🔍