Rule Document 1:66502

Rule Category

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

Alert Message

SERVER-WEBAPP NGINX rewrite module remote code execution attempt

Rule Explanation

This rule looks for specific binary signatures in the HTTP client body that indicate a crafted payload targeting the NGINX rewrite module heap overflow. Successful exploitation allows an attacker to execute arbitrary code on the server.

What To Look For

This rule fires on attempts to exploit a remote code execution vulnerability in NGINX web servers.

Known Usage

Public information/Proof of Concept available

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

Rule Categories::Server::Web Applications

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.

MITRE::ATT&CK Framework::Enterprise::Impact::Endpoint Denial of Service::Application or System Exploitation

Vulnerability::Severity::Critical

Vulnerability::Severity::High

CVE

CVE-2026-42945

Additional Links

my.f5.com/manage/s/article/K000161019

Rule Vulnerability

Buffer Overflow

Buffer Overflows occur when a memory location is filled past its expected boundaries. Computer attackers target systems without proper terminating conditions on buffers, which then write the additional information in other locations in memory, overwriting what is there. This could corrupt the data, making the system behave erratically or crash. The new information could include malicious executable code, which might be executed.

CVE Additional Information

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

CVE-2026-42945

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