Rule Document 1:67126

Rule Category

SERVER-WEBAPP -- Snort has detected traffic exploiting vulnerabilities in web based applications on servers.

Alert Message

SERVER-WEBAPP PaperCut NG/MF authentication bypass attempt

Rule Explanation

This rule looks for HTTP requests to the PaperCut application that contain the "service=direct" parameter followed by a public page identifier ("Error", "Exception", or "Home") and a privileged component path such as "ConfigEditor" or "UserList". Successful exploitation allows an unauthenticated attacker to invoke administrative functionality on the server.

What To Look For

This rule fires on attempts to bypass authentication in PaperCut NG/MF web applications.

Known Usage

Public information/Proof of Concept available

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

MITRE::ATT&CK Framework::Enterprise::Initial Access::Exploit Public-Facing Application

Adversaries may attempt to take advantage of a weakness in an Internet-facing computer or program using software, data, or commands in order to cause unintended or unanticipated behavior. The weakness in the system can be a bug, a glitch, or a design vulnerability. These applications are often websites, but can include databases (like SQL), standard services (like SMB or SSH), network device administration and management protocols (like SNMP and Smart Install), and any other applications with Internet accessible open sockets, such as web servers and related services.

Vulnerability::Severity::Critical

Vulnerability::Severity::High

CVE

CVE-2026-81578 CVE-2026-82078

Additional Links

www.papercut.com/kb/Main/security-bulletin-27-aug-2026-urgent-security-advisory/

Rule Vulnerability

Authentication Bypass

An Authentication Bypass occurs when there is a way to avoid providing user credentials to a system before performing restricted operations on said system.

CVE Additional Information

This product uses data from the NVD API but is not endorsed or certified by the NVD.

CVE-2026-81578

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CVE-2026-82078

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