High

Password Hash Interception and Replacement in Rockwell Automation Micro800 and MicroLogix 1400

IdentifiersCVE-2021-32926CWE-300· Channel Accessible by Non-Endpoint

CVE-2021-32926 is a vulnerability in Rockwell Automation Micro800 (all versions) and MicroLogix 1400 (version 21 and later) controllers. During an authenticated password change request, an attacker can intercept the message containing the new password hash and replace it with an illegitimate hash. This manipulation prevents the legitimate user from authenticating to the controller, resulting in a denial-of-service condition.

For your environment

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation allows an attacker to prevent legitimate users from accessing the controller by replacing the password hash during a password change operation. This results in a denial-of-service, as the user is locked out of the device.

Mitigation

If you can’t patch tonight, do this now.

Mitigate risk by ensuring strong network segmentation, restricting access to the controller management interfaces, and using secure communication channels (e.g., VPN, encrypted protocols) to prevent interception and tampering of password change requests.

Remediation

Patch, then assume compromise.

Apply vendor-provided patches or updates that address the vulnerability. If patches are not available, follow vendor guidance for secure configuration and network segmentation to reduce exposure.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Rockwell AutomationMicro800 Firmwareoperating_system

Rockwell AutomationMicrologix 1400 Firmwareoperating_system

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

1 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

1 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2021-32926

NVD

nvd.nist.gov/vuln/detail/CVE-2021-32926

MITRE CWE · CWE-300

Channel Accessible by Non-Endpoint

Third Party Advisory

us-cert.cisa.gov/ics/advisories/icsa-21-145-02