CVE-2017-9798

HIGH EXPLOITED RANSOMWARE

Apache httpd <2.4.28 - Use After Free

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2017-9798 has been observed exploited in the wild (reported by VulnCheck KEV), including in ransomware campaigns. EIP tracks 8 public exploits from researchers including Hanno Bock, brokensound77, nitrado, including a Metasploit module auxiliary/scanner/http/apache_optionsbleed.

AI-analyzed exploit summary This script tests for the Optionsbleed vulnerability (CVE-2017-9798) by sending OPTIONS requests to a target host and analyzing the 'Allow' header for anomalies such as duplicates, spaces, or corrupted data. It supports multiple URL prefixes and repeated testing to detect inconsistencies.

Description

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.

Exploits (8)

exploitdb SCANNER
by Hanno Bock · pythonwebappslinux
https://www.exploit-db.com/exploits/42745

This script tests for the Optionsbleed vulnerability (CVE-2017-9798) by sending OPTIONS requests to a target host and analyzing the 'Allow' header for anomalies such as duplicates, spaces, or corrupted data. It supports multiple URL prefixes and repeated testing to detect inconsistencies.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Apache HTTP Server (versions affected by CVE-2017-9798)
No auth needed
Prerequisites: Network access to the target host · Target host running a vulnerable version of Apache HTTP Server
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec SCANNER 18 stars
by brokensound77 · infoleak
https://github.com/brokensound77/OptionsBleed-POC-Scanner

This repository contains a scanner for CVE-2017-9798 (OptionsBleed), which exploits an information leak vulnerability in Apache HTTP Server. The scanner sends multiple HTTP OPTIONS and custom method requests to detect inconsistencies in the 'Allow' header responses.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server 2.2.x, 2.4.x
No auth needed
Prerequisites: Network access to the target server
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec SCANNER 3 stars
by nitrado · local
https://github.com/nitrado/CVE-2017-9798

This repository contains a Python script that scans for vulnerable .htaccess files affected by CVE-2017-9798. It checks for disallowed HTTP methods in <Limit> directives, which could lead to unauthorized access or privilege escalation.

Classification
Scanner 100%
Attack Type
Auth Bypass
Complexity
Trivial
Reliability
Reliable
Target: Apache HTTP Server with .htaccess configurations
No auth needed
Prerequisites: Access to the file system where .htaccess files are stored
devstral-2 · analyzed Feb 16, 2026 Full analysis →
nomisec SCANNER 2 stars
by pabloec20 · poc
https://github.com/pabloec20/optionsbleed

This PoC scans for CVE-2017-9798 (OptionsBleed), a vulnerability in Apache HTTP Server where the 'Allow' header may leak arbitrary memory content. The script sends OPTIONS requests and parses the response for unexpected data in the 'Allow' header.

Classification
Scanner 95%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Apache HTTP Server 2.2.x, 2.4.x
No auth needed
Prerequisites: Network access to the target server
devstral-2 · analyzed Feb 16, 2026 Full analysis →
github WORKING POC 1 stars
by vaishakhcv · perlpoc
https://github.com/vaishakhcv/CVE-exploits/tree/master/CVE-2017-9798

This repository contains a functional Perl script that exploits CVE-2017-9798 (OptionsBleed) in Apache HTTP Server by sending crafted OPTIONS requests to detect memory leakage in the Allow header. The script checks for irregular separators in the header to confirm vulnerability.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server (versions 2.2.x and 2.4.x with specific configurations)
No auth needed
Prerequisites: Apache server with misconfigured Limit directive (e.g., invalid HTTP method)
devstral-2 · analyzed Feb 27, 2026 Full analysis →
github WORKING POC
by winterwolf32 · perlpoc
https://github.com/winterwolf32/CVE_Exploits-/tree/master/CVE-2017-9798

This repository contains a functional Perl script that exploits CVE-2017-9798 (OptionsBleed) in Apache HTTP Server by sending crafted OPTIONS requests to detect memory leaks in the Allow header. The script checks for irregular separators in the header to confirm vulnerability.

Classification
Working Poc 95%
Attack Type
Info Leak
Complexity
Moderate
Reliability
Reliable
Target: Apache HTTP Server (versions affected by CVE-2017-9798)
No auth needed
Prerequisites: Apache HTTP Server with misconfigured Limit directive (e.g., invalid HTTP method)
devstral-2 · analyzed Feb 27, 2026 Full analysis →
nomisec SCANNER
by l0n3rs · local
https://github.com/l0n3rs/CVE-2017-9798

This repository contains a Python script that scans for vulnerable .htaccess files affected by CVE-2017-9798. It checks for disallowed HTTP methods within <Limit> directives, which could lead to unauthorized access or privilege escalation.

Classification
Scanner 100%
Attack Type
Auth Bypass
Complexity
Trivial
Reliability
Reliable
Target: Apache HTTP Server (versions with vulnerable .htaccess configurations)
No auth needed
Prerequisites: Access to the file system where .htaccess files are stored
devstral-2 · analyzed Feb 16, 2026 Full analysis →
metasploit SCANNER
by Hanno Böck, h00die · rubypoc
https://github.com/rapid7/metasploit-framework/blob/master/modules/auxiliary/scanner/http/apache_optionsbleed.rb

This Metasploit module scans for the Apache Optionsbleed vulnerability (CVE-2017-9798) by sending OPTIONS requests and analyzing the Allow header for memory leakage or other bugs. It checks for repeated or malformed method lists in the response.

Classification
Scanner 100%
Attack Type
Info Leak
Complexity
Trivial
Reliability
Reliable
Target: Apache HTTP Server (versions 2.2.x, 2.4.x)
No auth needed
Prerequisites: Network access to the target Apache server · Presence of a vulnerable .htaccess file with an invalid Limit method
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (56)

Core 56
Core References
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3113
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/100872
Patch, Third Party Advisory x_refsource_confirm
http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
Patch, Third Party Advisory x_refsource_confirm
http://www.oracle.com/technetwork/security-advisory/cpujan2018-3236628.html
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:2882
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:2972
Exploit, Patch, Technical Description, Third Party Advisory x_refsource_misc
https://blog.fuzzing-project.org/uploads/apache-2.2-optionsbleed-backport.patch
Third Party Advisory x_refsource_confirm
https://support.apple.com/HT208331
Third Party Advisory, VDB Entry vdb-entry x_refsource_sectrack
http://www.securitytracker.com/id/1039387
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3475
Exploit, Third Party Advisory x_refsource_misc
https://github.com/hannob/optionsbleed
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3240
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3195
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3018
Patch, Third Party Advisory x_refsource_confirm
http://www.oracle.com/technetwork/security-advisory/cpuapr2018-3678067.html
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3239
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3476
Third Party Advisory, VDB Entry vdb-entry x_refsource_bid
http://www.securityfocus.com/bid/105598
Patch, Third Party Advisory x_refsource_confirm
http://www.oracle.com/technetwork/security-advisory/cpuoct2018-4428296.html
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3114
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3477
Mailing List, VDB Entry x_refsource_misc
http://openwall.com/lists/oss-security/2017/09/18/2
Third Party Advisory x_refsource_confirm
https://security.netapp.com/advisory/ntap-20180601-0003/
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3194
Third Party Advisory x_refsource_misc
https://security-tracker.debian.org/tracker/CVE-2017-9798
Third Party Advisory vendor-advisory x_refsource_redhat
https://access.redhat.com/errata/RHSA-2017:3193
Third Party Advisory vendor-advisory x_refsource_debian
http://www.debian.org/security/2017/dsa-3980
Exploit, Patch, Technical Description, Third Party Advisory x_refsource_misc
https://blog.fuzzing-project.org/60-Optionsbleed-HTTP-OPTIONS-method-can-leak-Apaches-server-memory.html
Exploit, Third Party Advisory, VDB Entry exploit x_refsource_exploit-db
https://www.exploit-db.com/exploits/42745/
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/201710-32
Third Party Advisory x_refsource_confirm
https://www.tenable.com/security/tns-2019-09

Scores

CVSS v3 7.5
EPSS 0.9500
EPSS Percentile 99.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Details

VulnCheck KEV 2022-02-22
Ransomware Use Confirmed
CWE
CWE-416
Status published
Products (23)
apache/http_server 2.4.0
apache/http_server 2.4.1
apache/http_server 2.4.2
apache/http_server 2.4.3
apache/http_server 2.4.4
apache/http_server 2.4.6
apache/http_server 2.4.7
apache/http_server 2.4.9
apache/http_server 2.4.10
apache/http_server 2.4.12
... and 13 more
Published Sep 18, 2017
Tracked Since Feb 18, 2026