CVE-2016-8740: Input Validation

Published Dec 5, 2016
·
Updated

apache. Multiple issues existed in Apache. These were addressed by updating Apache to version 2.4.25.

Other sources

apache. Multiple issues were addressed by updating to version 2.4.27.

The HTTP/2 protocol implementation (modhttp2) had an incomplete handling of the LimitRequestFields directive. This allowed an attacker to inject unlimited request headers into the server, leading to eventual memory exhaustion.

Affects all versions from 2.4.17 to 2.4.23.

Mitigation:

As a temporary workaround - HTTP/2 can be disabled by changing the configuration by removing h2 and h2c from the Protocols line(s) in the configuration file.

The resulting line should read:

Protocols http/1.1

External References:

https://httpd.apache.org/security/vulnerabilities24.html http://seclists.org/bugtraq/2016/Dec/3

Red Hat

The modhttp2 module in the Apache HTTP Server 2.4.17 through 2.4.23, when the Protocols configuration includes h2 or h2c, does not restrict request-header length, which allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.

MITRE

Credit

CVE-2016-0736, CVE-2016-2161, CVE-2016-5387, CVE-2016-8740, CVE-2016-8743, CVE-2017-3167, CVE-2017-3169, CVE-2017-7659, CVE-2017-7668, CVE-2017-7679, CVE-2017-9788, CVE-2017-9789

Affected Software

12 affected componentsFixes available
redhat/httpd<2.4.24
2.4.24
Apple macOS High Sierra<10.13
10.13
Apple macOS High Sierra<10.13.1
10.13.1
Apple Sierra
Apple El Capitan
Apache HTTP Server=2.4.17
Apache HTTP Server=2.4.18
Apache HTTP Server=2.4.19
Apache HTTP Server=2.4.20
Apache HTTP Server=2.4.21
Apache HTTP Server=2.4.22
Apache HTTP Server=2.4.23

Event History

Dec 5, 2016
Data Sourced
via Red Hat·02:06 PM
DescriptionSeverityAffected Software
CVE Published
via MITRE·07:00 PM
Data Sourced
via MITRE·07:00 PM
Description

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is CVE-2016-8740?

CVE-2016-8740 is a vulnerability in the Apache HTTP Server that allows remote attackers to cause a denial of service (memory consumption) via crafted CONTINUATION frames in an HTTP/2 request.

2

How does CVE-2016-8740 affect Apache HTTP Server?

CVE-2016-8740 affects Apache HTTP Server versions 2.4.17 through 2.4.23 when the Protocols configuration includes h2 or h2c. It does not restrict request-header length, allowing remote attackers to cause a denial of service.

3

What is the severity of CVE-2016-8740?

CVE-2016-8740 has a severity rating of 7.5 (High).

4

How can I fix CVE-2016-8740?

To fix CVE-2016-8740, update your Apache HTTP Server to version 2.4.27 or later.

5

Where can I find more information about CVE-2016-8740?

You can find more information about CVE-2016-8740 at the following references: [1] https://httpd.apache.org/security/vulnerabilities_24.html [2] http://seclists.org/bugtraq/2016/Dec/3 [3] https://bugzilla.redhat.com/show_bug.cgi/show_bug.cgi?id=1401530

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