Rule Category

SERVER-APACHE -- Snort has detected traffic exploiting vulnerabilities in Apache servers.

Alert Message

SERVER-APACHE Apache HTTP Server possible OPTIONS method memory leak attempt

Rule Explanation

Apache HTTP Server versions 2.2.34 and 2.4.x through 2.4.27 are vulnerable to a memory leak via the HTTP OPTIONS method. This rule looks for multiple attempts being made using the OPTIONS method to a target system.

What To Look For

This event is generated when multiple HTTP OPTIONS methods are set to a target system.

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Exfiltration

Technique: Exfiltration Over Other Network Medium

For reference, see the MITRE ATT&CK vulnerability types here: https://attack.mitre.org

CVE

Additional Links

Rule Vulnerability

CVE Additional Information

CVE-2017-9798
Apache httpd allows remote attackers to read secret data from process memory if the Limit directive can be set in a user's .htaccess file, or if httpd.conf has certain misconfigurations, aka Optionsbleed. This affects the Apache HTTP Server through 2.2.34 and 2.4.x through 2.4.27. The attacker sends an unauthenticated OPTIONS HTTP request when attempting to read secret data. This is a use-after-free issue and thus secret data is not always sent, and the specific data depends on many factors including configuration. Exploitation with .htaccess can be blocked with a patch to the ap_limit_section function in server/core.c.
Details
Severity Base Score7.5
Impact Score3.6 Exploit Score3.9
Confidentiality ImpactHIGH Integrity ImpactNONE
Availability ImpactNONE Access Vector
Authentication Ease of Access