Apache HTTP Server, in all releases prior to 2.2.32 and 2.4.25, was liberal in the whitespace accepted from requests and sent in response lines and headers. Accepting these different behaviors represented a security concern when httpd participates in any chain of proxies or interacts with back-end application servers, either through modproxy or using conventional CGI mechanisms, and may result in request smuggling, response splitting and cache pollution.

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

Off-by-one error in the ldap scheme handling in the Rewrite module (modrewrite) in Apache 1.3 from 1.3.28, 2.0.46 and other versions before 2.0.59, and 2.2, when RewriteEngine is enabled, allows remote attackers to cause a denial of service (application crash) and possibly execute arbitrary code via crafted URLs that are not properly handled using certain rewrite rules.

An Uncontrolled Resource Consumption vulnerability in multiple products may allow an attacker to cause web service portal denial of service (DoS) via handling special crafted HTTP requests/responses in pieces slowly. Slow HTTP attacks are denial-of-service (DoS) attacks in which the attacker sends HTTP requests in pieces slowly, one at a time to a Web server. If an HTTP request is not complete, or if the transfer rate is very low, the server keeps its resources busy waiting for the rest of the data. When the server’s concurrent connection pool reaches its maximum, this creates a DoS. Slow HTTP attacks are easy to execute because they require only minimal resources from the attacker.

Martin Joey Schulze discovered a flaw in the way modauthmysql handles certain multibyte character encodings.

If modauthmysql is configured to use use a multibyte character set that allows the backslash '\' character as part of the character encodings, it is possible to inject arbitrary SQL commands to the MySQL database server.

The Solaris pollset feature in the Event Port backend in poll/unix/port.c in the Apache Portable Runtime (APR) library before 1.3.9, as used in the Apache HTTP Server before 2.2.14 and other products, does not properly handle errors, which allows remote attackers to cause a denial of service (daemon hang) via unspecified HTTP requests, related to the prefork and event MPMs.

The expat XML parser in the aprxml interface in xml/aprxml.c in Apache APR-util before 1.3.7, as used in the moddav and moddavsvn modules in the Apache HTTP Server, allows remote attackers to cause a denial of service (memory consumption) via a crafted XML document containing a large number of nested entity references, as demonstrated by a PROPFIND request, a similar issue to CVE-2003-1564.

The streamreqbodycl function in modproxyhttp.c in the modproxy module in the Apache HTTP Server before 2.3.3, when a reverse proxy is configured, does not properly handle an amount of streamed data that exceeds the Content-Length value, which allows remote attackers to cause a denial of service (CPU consumption) via crafted requests.

François Guerraz reported in Debian BTS a possible DoS (CPU consumption) a DoS with moddeflate since it does not stop to compress large files even after the network connection has been closed. This allows to use large amounts of CPU if there is a largish file available that has moddeflate enabled.

Original report: http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=534712

Post to the apache-httpd-dev mailing list: http://marc.info/?l=apache-httpd-dev&m=124621326524824&w=2

An exploit was posted to full-disclosure labelled "Apache Killer". This script creates a number of threads that use multiple Range headers to exhaust memory on the Apache server.

The ASF httpd development team are working on a fix for this issue: http://www.gossamer-threads.com/lists/apache/dev/401638