Rule Category

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

Alert Message

SERVER-WEBAPP Squid ESI processing buffer overflow attempt

Rule Explanation

Squid Proxy is vulnerable to a buffer overflow attack using crafted Edge Side Includes in a response. This could allow for an attacker to gain remote code execution.

What To Look For

This rule looks for a buffer overflow in Squid Proxy service.

Known Usage

Public information/Proof of Concept available

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Initial Access

Technique: Exploit Public-Facing Application

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

CVE

Additional Links

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

CVE-2016-4054
Buffer overflow in Squid 3.x before 3.5.17 and 4.x before 4.0.9 allows remote attackers to execute arbitrary code via crafted Edge Side Includes (ESI) responses.
Details
Severity Base Score8.1
Impact Score5.9 Exploit Score2.2
Confidentiality ImpactHIGH Integrity ImpactHIGH
Availability ImpactHIGH Access Vector
Authentication Ease of Access