Rule Category

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

Alert Message

SERVER-WEBAPP PHP tag depth heap memory corruption attempt

Rule Explanation

This rule attempts to identify payloads with deeply nested XML documents.

What To Look For

This rule alerts when an attempt to exploit a heap memory overflow deficiency in PHP before 5.3.27

Known Usage

No public information

False Positives

No known false positives

Contributors

Cisco Talos Intelligence Group

MITRE ATT&CK Framework

Tactic: Impact

Technique: Network Denial of Service

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

CVE

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-2013-4113
ext/xml/xml.c in PHP before 5.3.27 does not properly consider parsing depth, which allows remote attackers to cause a denial of service (heap memory corruption) or possibly have unspecified other impact via a crafted document that is processed by the xml_parse_into_struct function.
Details
SeverityMEDIUM Base Score6.8
Impact Score6.4 Exploit Score8.6
Confidentiality ImpactPARTIAL Integrity ImpactPARTIAL
Availability ImpactPARTIAL Access Vector
AuthenticationNONE Ease of Access