Low

Improper PLC Application Integrity Check in CODESYS Control Runtime

IdentifiersCVE-2023-28355CWE-354

CVE-2023-28355 is an improper validation of integrity check value vulnerability in the CODESYS Control Runtime used in Schneider Electric devices that embed the CODESYS Runtime System V3. The PLC application code executed by the runtime relies on a checksum mechanism that is not sufficient to reliably detect PLC application code modified in memory or boot application files that have been manipulated. As a result, the integrity verification mechanism can be bypassed by altered application content, allowing unauthorized modifications to persist without dependable detection by the runtime.

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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 can compromise the integrity of PLC application code and boot application files on affected devices. An attacker with the necessary access could alter control logic or runtime-resident application content without reliable detection by the checksum mechanism, enabling unauthorized changes to industrial process behavior. The documented impact is integrity loss rather than confidentiality or availability loss, reflected by CVSS v3.1 6.5 with high integrity impact.

Mitigation

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

Restrict access to device programming and engineering interfaces, enable user management with strong authentication, and use encrypted communication links where supported. Limit exposure of programming ports to trusted administrative networks only, segment control networks behind firewalls, and use secure remote access methods such as VPNs. Minimize direct network reachability of affected controllers and HMIs from untrusted networks to reduce the likelihood of authenticated tampering.

Remediation

Patch, then assume compromise.

Apply Schneider Electric firmware and software updates for affected products that incorporate the vendor-provided fixes for the underlying CODESYS runtime issue. Reported fixed versions include updates delivered through EcoStruxure Machine Expert v2.2 for certain Modicon and PacDrive product lines, Vijeo Designer 6.3.1 or later for affected HMISCU-related components, and other product-specific updates identified by Schneider Electric. For legacy end-of-life products where no fix is planned, migration to supported replacement platforms is recommended.

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.

ACTIVITY FEED

Recent activity

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

4 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

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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