Apache HTTP Server up to 2.4.23 mod_http2 h2_stream.c input validation

CVSS Meta Temp Score
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CTI Interest Score
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6.1$0-$5k0.00

A vulnerability was found in Apache HTTP Server up to 2.4.23 (Web Server). It has been declared as problematic. This vulnerability affects an unknown code of the file modules/http2/h2_stream.c of the component mod_http2. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect availability.

The weakness was presented 12/05/2016 by Naveen Tiwari, CDF and SEFCOM as CVE-2016-8740, Server memory can be exhausted and service denied when HTTP/2 is used as confirmed mailinglist post (Bugtraq). The advisory is available at seclists.org. The public release was coordinated in cooperation with the vendor. This vulnerability was named CVE-2016-8740. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details and also a public exploit are known. The advisory points out:

From version 2.4.17, upto and including version 2.4.23 the server failed to take the limitations on request memory use into account when providing access to a resource over HTTP/2.

It is possible to download the exploit at exploit-db.com. It is declared as proof-of-concept. As 0-day the estimated underground price was around $25k-$100k. The vulnerability scanner Nessus provides a plugin with the ID 96037 (FreeBSD : Apache httpd -- several vulnerabilities (862d6ab3-c75e-11e6-9f98-20cf30e32f6d) (httpoxy)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family FreeBSD Local Security Checks. The commercial vulnerability scanner Qualys is able to test this issue with plugin 370348 (Apple Mac OS X Security Update Sierra 10.12.4, El Capitan 2017-001 and Yosemite 2017-001 Not Installed (APPLE-SA-2017-03-27-3)).

Upgrading to version 2.4.23 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at seclists.org. The best possible mitigation is suggested to be upgrading to the latest version. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (96037) and Exploit-DB (40909). See 89669, 89849, 94625 and 94626 for similar entries.

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CPE 2.3info

CPE 2.2info

CVSSv4info

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CVSSv3info

VulDB Meta Base Score: 6.4
VulDB Meta Temp Score: 6.1

VulDB Base Score: 5.3
VulDB Temp Score: 4.8
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NVD Base Score: 7.5
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CVSSv2info

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Exploitinginfo

Class: Input validation
CWE: CWE-20
ATT&CK: Unknown

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

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Nessus ID: 96037
Nessus Name: FreeBSD : Apache httpd -- several vulnerabilities (862d6ab3-c75e-11e6-9f98-20cf30e32f6d) (httpoxy)
Nessus File: 🔍
Nessus Risk: 🔍
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OpenVAS ID: 841282
OpenVAS Name: Fedora Update for httpd FEDORA-2016-b39fedec11
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Threat Intelligenceinfo

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Countermeasuresinfo

Recommended: Upgrade
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Upgrade: HTTP Server 2.4.23
Patch: seclists.org

Timelineinfo

10/18/2016 🔍
12/05/2016 +48 days 🔍
12/05/2016 +0 days 🔍
12/05/2016 +0 days 🔍
12/05/2016 +0 days 🔍
10/05/2022 +2130 days 🔍

Sourcesinfo

Vendor: apache.org

Advisory: CVE-2016-8740, Server memory can be exhausted and service denied when HTTP/2 is used
Researcher: Naveen Tiwari, CDF, SEFCOM
Status: Confirmed
Coordinated: 🔍

CVE: CVE-2016-8740 (🔍)
SecurityTracker: 1037388
SecurityFocus: 94650

scip Labs: https://www.scip.ch/en/?labs.20161013
See also: 🔍

Entryinfo

Created: 12/05/2016 17:08
Updated: 10/05/2022 06:50
Changes: 12/05/2016 17:08 (54), 04/16/2019 15:11 (19), 10/05/2022 06:28 (5), 10/05/2022 06:40 (11), 10/05/2022 06:50 (1)
Complete: 🔍

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