Two backdoors in Juniper ScreenOS

Published: 2015-12-17 | Updated: 2017-03-24

Risk	Critical
Patch available	YES
Number of vulnerabilities	2
CVE-ID	CVE-2015-7755 CVE-2015-7756
CWE-ID	CWE-287 CWE-327
Exploitation vector	Network
Public exploit	Vulnerability #1 is being exploited in the wild. Vulnerability #2 is being exploited in the wild.
Vulnerable software Subscribe	Juniper ScreenOS Operating systems & Components / Operating system
Vendor	Juniper Networks, Inc.

Security Bulletin

This security bulletin contains information about 2 vulnerabilities.

1) Authentication bypass

EUVDB-ID: #VU5587

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 - Improper Authentication

Exploit availability: Yes

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

External links

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

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.

2) Information disclosure

EUVDB-ID: #VU5889

Risk: High

CVSSv3.1: 4.9 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N/E:F/RL:O/RC:C]

CVE-ID: CVE-2015-7756

CWE-ID: CWE-327 - Use of a Broken or Risky Cryptographic Algorithm

Exploit availability: No

Description

The vulnerability allows a remote attacker to obtain potentially sensitive information on the target system.

The weakness exists due to usage of insecure encryption keys. A remote attacker can with ability to monitor VPN traffic can intercept and decrypt it.

Successful exploitation of the vulnerability results in information disclosure on the target system.

Note: the vulnerability was disclosed as part of two backdoors during internal source code audit.