Medium

Denial of Service via Malformed .NET RPC Packet in OPC Systems.NET

IdentifiersCVE-2011-4871CWE-20· Improper Input Validation

A remotely exploitable vulnerability exists in Open Automation Software OPC Systems.NET prior to version 5.0, where the application fails to properly validate .NET RPC packets received on TCP port 58723. An attacker can send a specially crafted, malformed packet to this port, causing the service to crash and resulting in a denial of service condition. This vulnerability was publicly disclosed and affects all versions prior to 5.0.

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 a remote attacker to crash the OPC Systems.NET service, leading to a denial of service. This can disrupt SCADA/HMI operations in critical infrastructure sectors such as manufacturing, energy, water, and defense. The vulnerability does not allow code execution or privilege escalation, but the operational impact can be significant in environments relying on continuous availability.

Mitigation

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

Minimize network exposure of OPC Systems.NET instances, ensuring they are not accessible from untrusted networks. Isolate control system networks from business networks and use secure remote access methods such as VPNs. Implement defense-in-depth strategies and monitor for suspicious activity on TCP port 58723.

Remediation

Patch, then assume compromise.

Upgrade OPC Systems.NET to version 5.0 or later, which addresses this vulnerability. Ensure all affected systems are updated to the latest version provided by Open Automation Software.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.

VALID 0 / 1 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

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

OpcsystemsOpcsystems.Netapplication

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

ACTIVITY FEED

Recent activity

No public activity tracked yet. Mallory keeps watching.

0 SOURCESView more in app

No public activity observed for this vulnerability.

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