#VU6699 Authentication bypass in Allen-Bradley MicroLogix 1400 and Allen-Bradley MicroLogix 1100 - CVE-2017-7903

Vulnerability identifier: #VU6699

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2017-7903

CWE-ID: CWE-521

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Allen-Bradley MicroLogix 1400
Hardware solutions / Office equipment, IP-phones, print servers
Allen-Bradley MicroLogix 1100
Hardware solutions / Office equipment, IP-phones, print servers

Vendor: Rockwell Automation

Description
The vulnerability allows a remote attacker to perform brute-force attack.

The vulnerability exists due to weak password requirements. A remote attacker can brute-force account passwords and bypass authentication on the system.

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

Mitigation
Update to version 21.00

Vulnerable software versions

Allen-Bradley MicroLogix 1400: 1766-L32AWAA 16.00 - 1766-L32AWA 16.00

Allen-Bradley MicroLogix 1100: 1763-L16DWD 16.00 - 1763-L16AWA 16.00

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External links
https://ics-cert.us-cert.gov/advisories/ICSA-17-115-04

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.