September 26, 2016

Google expands its patch reward program

google logoIn early October Google launched its patch reward program that awards members of the open source community for making security improvements to open source projects. The program was designed to more than just a open source bug hunting exhibition but rather a way to provide financial incentives for proactive security enhancements that go beyond fixing a known security vulnerability.

The project started out quite small in scope with Google only considering patches for projects like OpenSSH, BIND, ISC DHCP, libjpeg, libjpeg-turbo, libpng, giflib and OpenSSL. To qualify patches need to be submitted to the maintainers of the individual projects and then Google need to be notified about the improvements. If Google considers the submission has a positive impact on security then the coder qualifies for a reward ranging from $500 to $3,133.7.

Now after almost six weeks of running the initial program Google has announced that it is ready to expand the program to include more open source projects including Android. The full list of new projects now eligible for rewards are:

  • All the open-source components of Android: Android Open Source Project
  • Widely used web servers: Apache httpd, lighttpd, nginx
  • Popular mail delivery services: Sendmail, Postfix, Exim, Dovecot
  • Virtual private networking: OpenVPN
  • Network time: University of Delaware NTPD
  • Additional core libraries: Mozilla NSS, libxml2
  • Toolchain security improvements for GCC, binutils, and llvm

The inclusion of Android is interesting as it shows that Google is keen to continue making security improvements to its very popular mobile operating system. Recently Google has added SELinux and nosuid protection to Android as well as creating a free built-in service called Verify Apps. Available for all versions of Android from 2.3 onwards, Verify Apps behaves very much like an antivirus scanner and blocks the installation of malicious software, regardless of the source.

In the past Android has been seen as less secure than Apple’s iOS primarily because Android allows users to install apps from anywhere not just from Google’s Play Store. Since Apple maintains a walled garden and only allows apps into its store after rigorous testing it means that malware scares have been less prominent on iOS. Vendors of Android security software suites seem to constantly write sensational headlines about how many new variants of Android malware are being created each month. Although technically they are right, users who stick to Google’s Play Store shouldn’t be in any danger.

Eight Year Old PHP / Apache mod_cgi Vulnerability Disclosed

(LiveHacking.Com) – Due to a bug in PHP’s bug tracking system, a privately disclosed security vulnerability in the way PHP handles query string parameters when it is running in CGI mode, was marked as public. As a result the PHP project has released PHP 5.3.12 and PHP 5.4.2 to fix the problem, however there are reports that these releases are buggy and don’t fully resolve the problem.

The initial details of the generic PHP-CGI remote code execution bug were posted on the website. They discovered that the query string ‘?-s’ results in the “-s” command line argument being passed to PHP, resulting in source code disclosure. Further investigation showed that the command-line switches -s, -d or -c are passed to the php-cgi binary, which can also be exploited to obtain arbitrary code execution.

To test if your site is vulnerable try the following:

According to the release information: “A large number of sites run PHP as either an Apache module through mod_php or using php-fpm under nginx. Neither of these setups are vulnerable to this. Straight shebang-style CGI also does not appear to be vulnerable. If you are using Apache mod_cgi to run PHP you may be vulnerable.”

The official fix in PHP 5.3.12 and PHP 5.4.2 contain a bug which makes the fix trivial to bypass, it is therefore recommended that system admins mitigate this problem by adding the following Apache mod_rewrite rule:

RewriteCond %{QUERY_STRING} ^(%2d|-)[^=]+$ [NC]
RewriteRule ^(.*) $1? [L]

The bug was originally discovered in January and was used to pwn the Nullcon Hackim 2012 scoreboard. The PHP team were contacted but after a couple of weeks little seemed to be happening. US-CERT was contacted who acknowledged the receipt of vulnerability in February. By May US-CERT notified that the PHP team was testing a patch. However on May 3rd the bug reported was mistakenly marked as public and picked up on reddit /r/netsec /r/opensource and /r/technology. US-CERT have now published a Vulnerability Note.

It is anticipated that a new PHP update, with a revised fix, will be released soon.

Apple Releases Security Updates for OS X

(LiveHacking.Com) – Apple has released security updates for Apple OS X Lion 10.7 and Mac OS X Snow Leopard 10.6 to fix multiple vulnerabilities. These vulnerabilities could allow an attacker to execute arbitrary code, cause a denial-of-service condition, obtain sensitive information, and bypass security restrictions. The update is an amalgamation of recent security updates for several different components used by Apple (including Apache and PHP) along with fixes for Apple’s own code.

3rd Party

This release brings some of OS X’s third party components up to date including:

Apache: There are known attacks on the confidentiality of SSL 3.0 and TLS 1.0 when a cipher suite uses a block cipher in CBC mode. Apache disabled the ’empty fragment’ countermeasure which prevented these attacks. This issue is addressed by providing a configuration parameter to control the countermeasure and enabling it by default.

PHP is updated to version 5.3.8 to address several vulnerabilities, the most serious of which may lead to arbitrary code execution. However, it is worth noting that PHP 5.3.10 has since been released to fix the hash table collisions problem that affected all the popular Web programming languages (including PHP, ASP.NET, Ruby and Python).

SquirrelMail is updated to version 1.4.22 to address several vulnerabilities, the most serious of which is a cross-site scripting issue. This issue does not affect OS X Lion systems.

Tomcat is updated to version 6.0.33 to address multiple vulnerabilities, the most serious of which may lead to the disclosure of sensitive information. Tomcat is only provided on Mac OS X Server systems.

X11: A memory corruption issue existed in FreeType’s handling of Type 1 fonts. This issue is addressed by updating FreeType to version 2.4.7.

The update also revokes the trust for root certificates issued by DigiCert Malaysia. Two certificate authorities in the list of trusted root certificates have independently issued intermediate certificates to DigiCert Malaysia. Back in November it was discovered that DigiCert Malaysia had issued certificates with weak keys that it was unable to revoke.


Apple components that are updated include:

Address Book supports Secure Sockets Layer (SSL) for accessing CardDAV. A downgrade issue caused Address Book to attempt an unencrypted connection if an encrypted connection failed. An attacker in a privileged network position could abuse this behavior to intercept CardDAV data. This issue is addressed by not downgrading to an unencrypted connection without user approval.

CoreAudio: Playing maliciously crafted audio content may lead to an unexpected application termination or arbitrary code execution. A buffer overflow existed in the handling of AAC encoded audio streams.

CoreMedia: A heap buffer overflow existed in CoreMedia’s handling of H.264 encoded movie files.

QuickTime has been updated to resolve several issues including:

  • Opening a maliciously crafted MP4 encoded file may lead to an unexpected application termination or arbitrary code execution. An uninitialized memory access issue existed in the handling of MP4 encoded files.
  • Viewing a maliciously crafted movie file may lead to an unexpected application termination or arbitrary code execution. A signedness issue existed in the handling of font tables embedded in QuickTime movie files.
  • Viewing a maliciously crafted JPEG2000 image file may lead to an unexpected application termination or arbitrary code execution. A buffer overflow existed in the handling of JPEG2000 files.
  • Processing a maliciously crafted PNG image may lead to an unexpected application termination or arbitrary code execution. A buffer overflow existed in the handling of PNG files.

Time Machine: The user may designate a remote AFP volume or Time Capsule to be used for Time Machine backups. Time Machine did not verify that the same device was being used for subsequent backup operations. An attacker who is able to spoof the remote volume could gain access to new backups created by the user’s system. This issue is addressed by verifying the unique identifier associated with a disk for backup operations.

Apache Reverse Proxy Vulnerability Exposes Internal Servers

(LiveHacking.Com) – The Apache foundation has issued a security advisory regarding the use of the Apache HTTP Server in reverse proxy mode. If the server is configured using the RewriteRule or ProxyPassMatch directives with pattern matching, it is possible to unintentionally expose servers on your internal network that should be hidden by your firewall.

The problem is that the Apache HTTP server does not check that the incoming URL is valid. This means that attackers who send specially formed requests can force the pattern matching algorithms to expand the input to an unintended target URL.

The problem was originally found by Context Information Security Ltd who then worked with Apache to produce a patch which reduces the risks of an attacker exploiting a misconfigured server.

According to the advisory:

For future releases of the Apache HTTP Server, the software will validate the request URI, correcting this specific vulnerability. For future releases, the server has been patched to reject such requests, instead returning a “400 Bad Request” error. The documentation has been updated to reflect the more general risks with pattern matching in a reverse proxy configuration.


A configuration like one of the following examples:

RewriteRule (.*)\.(jpg|gif|png)$1.$2 [P]
ProxyPassMatch (.*)\.(jpg|gif|png)$1.$2

could result in an exposure of internal servers. A request of the form:


would get translated to a target of: () other example com/something.png

This will cause the proxy to connect to the hostname “”, as the “” segment would be treated as user credentials when parsing the URL. This would allow a remote attacker the ability to proxy to hosts other than those expected, which could be a security exposure in some circumstances.

The request-URI string in this example, “”, is not valid according to the HTTP specification, since it neither an absolute URI
(“”;) nor an absolute path (“/path”).


The Apache foundation have released a patch and also recommend system administrators check the use of the RewriteRule and change them according to the example below:

RewriteRule (.*)\.(jpg|gif|png)$1.$2 [P]
RewriteRule /(.*)\.(jpg|gif|png)$1.$2 [P]

to ensure the pattern only matches against paths starting with a “/”.

Oracle Issues Patches for Apache Byterange Filter Bug

Oracle has issued a special security alert for Oracle HTTP Server products that are based on Apache 2.0 or 2.2. The alert covers CVE-2011-3192 or the Apache HTTPD byterange filter exploit as it is more commonly known.

In August a bug was found in the Apache HTTPD server regarding how it byte range headers. By exploiting the bug, remote attackers can cause a denial of service (memory and CPU consumption) attack by sending Range header that express multiple overlapping ranges. A fix was released at the end of August and a few days ago a “more efficient” fix was released. Oracle are basically playing catchup by issuing this alert now.

Affected Oracle Products and Versions

  • Oracle Fusion Middleware 11g Release 1, versions,,
  • Oracle Application Server 10g Release 3, version (Only affected when Oracle HTTP Server 10g based on Apache 2.0 has been installed from Application Server Companion CD)
  • Oracle Application Server 10g Release 2, version (Only affected when Oracle HTTP Server 10g based on Apache 2.0 has been installed from Application Server Companion CD)
Due to the threat posed by a successful attack, Oracle strongly recommends that customers apply Security Alert fixes as soon as possible.

New Apache Version with Further Fixes for Handling Byte-range Requests

(LiveHacking.Com) – The Apache Foundation has released version 2.2.21 of the Apache HTTP Server. This version of Apache is mainly a security and bug fix release:

  • SECURITY: CVE-2011-3192 ( core: Further fixes to the handling of byte-range requests to use less memory, to avoid denial of service. This patch includes fixes to the patch introduced in release 2.2.20 for protocol compliance, as well as the MaxRanges directive.
  • SECURITY: CVE-2011-3348 ( mod_proxy_ajp when combined with mod_proxy_balancer: Prevents unrecognized HTTP methods from marking ajp: balancer members in an error state, avoiding denial of service.

A couple of weeks ago the discovery of a vulnerability in Apache left millions of web sites vulnerable to DoS attacks.  The problem revolves around how Apache handles byte range headers and was fixed in version 2.2.20. Apache 2.2.20 does fix this issue; however with a number of side effects. Version 2.2.21 corrects a protocol defect in 2.2.20, and also introduces the MaxRanges directive.

Apache HTTP Server 2.2.20 Released – Fixes Byte-range DoS Vulnerability

(LiveHacking.Com) – The Apache Foundation has released an update to its HTTPD server to fix the much publicized byte range headers problem.  The announcement notes just one fix:

  •  CVE-2011-3192: Fix handling of byte-range requests to use less memory, to avoid denial of service. If the sum of all ranges in a request is larger than the original file, ignore the ranges and send the complete file.

The vulnerability left over 60% of the world’s websites exposed to a denial of service attack. The problem revolved around how Apache handled byte range headers and due to a tool, which was published to demonstrate the problem, an attack could be easily  launched  and cause very significant memory and CPU usage on the target server.

Range Header DoS Vulnerability Leaves 60% of All Websites Open to Attack

(LiveHacking.Com) – Over 60% of the world’s websites are run using the Apache web server and a recently found vulnerability in Apache has left these millions of web sites open to a denial of service attack.

According to the official Apache HTTPD security advisory, the problem revolves around how Apache handles byte range headers. The advisory links to a tool which is available called “” which effectively demonstrates the problem. Active use of this tool has been observed. The attack can be done remotely and with a modest number of requests can cause very significant memory and CPU usage on a server.


Apache HTTPD users who are concerned about a DoS attack against their server should consider implementing any of the following mitigations immediately.

1) Use SetEnvIf or mod_rewrite to detect a large number of ranges and then either ignore the Range: header or reject the request.

Option 1: (Apache 2.0 and 2.2)
# Drop the Range header when more than 5 ranges.
# CVE-2011-3192
SetEnvIf Range (,.*?){5,} bad-range=1
RequestHeader unset Range env=bad-range

# optional logging.
CustomLog logs/range-CVE-2011-3192.log common env=bad-range

Option 2: (Also for Apache 1.3)
# Reject request when more than 5 ranges in the Range: header.
# CVE-2011-3192
RewriteEngine on
RewriteCond %{HTTP:range} !(^bytes=[^,]+(,[^,]+){0,4}$|^$)
RewriteRule .* - [F]

The number 5 is arbitrary. Several 10’s should not be an issue and may be required for sites which for example serve PDFs to very high end eReaders or use things such complex http based video streaming.

2) Use mod_headers to completely dis-allow the use of Range headers:

RequestHeader unset Range

Note that this may break certain clients – such as those used for e-Readers and progressive/http-streaming video.

A patch or new apache release for Apache 2.0 and 2.2 is expected
in the next 48 hours. Although still popular, Apache 1.3 is deprecated and as such there will be no official patch.

Apache 2.2.19 Released: Security Update and Bug-fix

The Apache HTTP Server Project team released the new version 2.2.19 of the Apache HTTP Server (httpd).

This new version is a security update and bug-fix release to address CVE-2011-1928 and CVE-2011-0419 DoS vulnerabilities. This release also corrects a versioning incompatibility in 2.2.18 and it is a major release of the stable branch, and represents the best available version of Apache HTTP Server according to the project’s website.

The Apache 2.2.19 includes some new features such as Smart Filtering, Improved Caching, AJP Proxy, Proxy Load Balancing, Graceful Shutdown support, Large File Support, the Event MPM, and refactored Authentication/Authorization.

This new release includes the Apache Portable Runtime (APR) version 1.4.5 and APR Utility Library (APR-util) version 1.3.12, bundled with the tar and zip distributions. The APR libraries libapr and libaprutil (and on Win32, libapriconv version 1.2.1) must all be updated to ensure binary compatibility and address many known security and platform bugs.

Apache HTTP Server 2.2.19 is available for download here.