Rule Category

SERVER-OTHER -- Snort has detected traffic exploiting vulnerabilities in a server in the network.

Alert Message

SERVER-OTHER OpenLDAP searchRequest denial of service attempt

Rule Explanation

This rule looks for LDAP searchRequest packets that contain the "certificateListExactMatch" filter OID followed by a "thisUpdate" attribute with an unusually short quoted value. Successful exploitation can cause the OpenLDAP service to crash, resulting in denial of service.

What To Look For

This rule fires on attempts to cause a denial of service condition in OpenLDAP servers via crafted searchRequest packets.

Known Usage

Public information/Proof of Concept available

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

Rule Groups

Rule Categories::Server::Other

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

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

Vulnerability::Severity::Critical

Vulnerability::Severity::High

Vulnerability::Severity::Medium

Vendors + Products::Debian::Linux

CVE

Additional Links

Rule Vulnerability

Denial of Service

Denial of Service attacks aim to make a server or program unresponsive for users. These attacks may be volume-based, to overwhelm the system, or they may use certain logical flaws in the software to cut the service off from the users. The attack may come from one or multiple sources. These attacks do not usually lead to a remote code execution. Volume based attacks are best handled using a firewall application.

CVE Additional Information

This product uses data from the NVD API but is not endorsed or certified by the NVD.
CVE-2021-27212
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