HighCISA KEVExploited in the wildPublic exploit

Device lockout in KNX Connection Authorization Option 1

IdentifiersCVE-2023-4346CWE-645· Overly Restrictive Account Lockout…

CVE-2023-4346 is an overly restrictive account lockout mechanism vulnerability affecting KNX devices that implement KNX Connection Authorization and support Option 1. In affected implementations, the BCU key feature can be used to create a device password that often cannot be reset without supplying the current password. An attacker who can interact with the KNX installation can purge devices that do not have additional security options enabled and then set a BCU key, placing the device into a locked state. The issue can be reached either through network access to a connected KNX installation or through direct physical access to the device, depending on deployment. The result is loss of administrative access and inability for legitimate users to reset the device and regain control through normal means.

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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 deny legitimate operators access to affected KNX devices by placing them into a locked state that cannot be reset without the attacker-defined current password. This can disrupt management and operation of building automation components, require device replacement or invasive recovery procedures, and impair availability of affected installations. In environments where multiple devices lack additional security protections, an attacker may be able to purge and lock multiple devices, amplifying operational disruption.

Mitigation

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

Restrict access to KNX networks to trusted administrators and isolated management segments, and prevent untrusted hosts from reaching KNX installations. Enable additional security options beyond Option 1 wherever supported. Limit physical access to field devices, controllers, and commissioning interfaces. Monitor for unauthorized purge operations or unexpected authorization changes, and avoid deploying affected devices in environments where attackers could obtain network or physical access until corrective vendor guidance is implemented.

Remediation

Patch, then assume compromise.

Apply vendor-provided fixes, firmware updates, or configuration changes for affected KNX devices where available. Prefer security configurations stronger than Connection Authorization Option 1, especially on devices exposed to shared or reachable KNX networks. Review affected deployments for devices that permit BCU key setting without a recoverable reset path, and replace or reconfigure products whose implementations remain vulnerable. Validate that recovery and reset procedures exist and can be performed without dependence on an attacker-controlled password.

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

KnxConnection Authorizationapplication

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

ACTIVITY FEED

Recent activity

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

10 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 signatures1

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 activity9

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

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2023-4346

NVD

nvd.nist.gov/vuln/detail/CVE-2023-4346

MITRE CWE · CWE-645

Overly Restrictive Account Lockout Mechanism

Third Party Advisory

cisa.gov/news-events/ics-advisories/icsa-23-236-01

US Government Resource

cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-4346

Device lockout in KNX Connection Authorization Option 1

IdentifiersCVE-2023-4346CWE-645· Overly Restrictive Account Lockout…