Vulnerability identifier: #VU5587

Vulnerability risk: Critical

CVSSv3.1: 8.2 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2015-7755

CWE-ID: CWE-287

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Juniper ScreenOS
Operating systems & Components / Operating system

Vendor: Juniper Networks, Inc.

Description
The vulnerability allows a remote attacker to bypass authentication on the target system.

The weakness exists due to presence of backdoor in Juniper ScreenOS code. A remote attacker can enter a password "<<< %s(un='%s') = %u" during a SSH or TELNET session and obtain administrative access to the device.

Successful exploitation of the vulnerability results in unauthorized access to the vulnerable system.

Note: the vulnerability was being actively exploited.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Juniper ScreenOS: 6.3.0r17 - 6.3.0r20

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External links
http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10713

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.