Rule Category

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

Alert Message

SERVER-WEBAPP Apache httpd ap_find_token buffer overread attempt

Rule Explanation

Multiple web servers contain buffer overflow vulnerabilities due to improper Connection header parsing. Impact: Details: Rule checks for attempts to trigger buffer overflow vulnerabilities in multiple web-servers via a maliciously crafted Connection header value. Ease of Attack:

What To Look For

This rule will alert when an attempt to exploit a known memory corruption vulnerability in Apache is detected.

Known Usage

No public information

False Positives

No known false positives

Contributors

Talos research team. This document was generated from data supplied by the national vulnerability database, a product of the national institute of standards and technology. For more information see [nvd].

MITRE ATT&CK Framework

Tactic: Execution

Technique: User Execution

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-2017-7668
The HTTP strict parsing changes added in Apache httpd 2.2.32 and 2.4.24 introduced a bug in token list parsing, which allows ap_find_token() to search past the end of its input string. By maliciously crafting a sequence of request headers, an attacker may be able to cause a segmentation fault, or to force ap_find_token() to return an incorrect value.
Details
Severity Base Score9.8
Impact Score5.9 Exploit Score3.9
Confidentiality ImpactHIGH Integrity ImpactHIGH
Availability ImpactHIGH Access Vector
Authentication Ease of Access