CVE-2017-7903: A Weak Password Requirements issue was discovered in Rockwell Automation Allen-Bradley MicroLogix 1100 prog...
A Weak Password Requirements issue was discovered in Rockwell Automation Allen-Bradley MicroLogix 1100 programmable-logic controllers 1763-L16AWA, Series A and B, Version 16.00 and prior versions; 1763-L16BBB, Series A and B, Version 16.00 and prior versions; 1763-L16BWA, Series A and B, Version 16.00 and prior versions; and 1763-L16DWD, Series A and B, Version 16.00 and prior versions and Allen-Bradley MicroLogix 1400 programmable logic controllers 1766-L32AWA, Series A and B, Version 16.00 and prior versions; 1766-L32BWA, Series A and B, Version 16.00 and prior versions; 1766-L32BWAA, Series A and B, Version 16.00 and prior versions; 1766-L32BXB, Series A and B, Version 16.00 and prior versions; 1766-L32BXBA, Series A and B, Version 16.00 and prior versions; and 1766-L32AWAA, Series A and B, Version 16.00 and prior versions. The affected products use a numeric password with a small maximum character size for the password.
Security readout for executives and security teams
This vulnerability affects certain Rockwell Automation Allen-Bradley MicroLogix 1100 and 1400 PLCs. The devices allow only weak numeric passwords with a small maximum length, making unauthorized access much easier if the device is reachable. Because PLCs control physical processes, compromise can affect operations, safety, and availability. Exposure is most concerning where affected PLCs are reachable from enterprise networks, remote-access paths, vendor support connections, or the internet. The source bundle does not confirm internet exposure or active targeting for specific environments. Treat as high-priority for OT environments using the affected PLCs. The issue is old but severe, and weak PLC authentication can create operational risk if devices are reachable. Prioritize inventory, exposure reduction, and vendor-guided remediation. Mitigation focus: Identify whether MicroLogix 1100 or 1400 PLCs are deployed.; Confirm model, series, and firmware version against the affected list.; Check Rockwell Automation and CISA advisory guidance for approved updates or mitigations..
Prepared
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Potential ATT&CK relevance
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CWE-521: Credential and account abuse lookup
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The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
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1CVSS vectors
3Timeline events
2ADP providers
2Source links
SSVC decision data
CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: total
CVSS vector scores
1 official score
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CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
CWE-521 · source CWE mapping
Weak Password Requirements
Weak Password Requirements represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.