Posts by author: Hendrik Buchwald

Non-Exploitable Security Issues

7 min read 10 Dec 2016 by Hendrik Buchwald
In our previous calendar posts, we covered specific security issues in popular open-source applications that were detected by our code analysis solution RIPS. Most of the released issues lead to remote command execution, the most critical security vulnerability in PHP applications. But are all findings always exploitable? For more diversity of our calendar, we would like to introduce a few interesting examples today that turned out to be not exploitable and how RIPS handles these scenarios.

Precurio 2.1: Remote Command Execution via Xinha Plugin

8 min read 9 Dec 2016 by Hendrik Buchwald
Precurio is an Intranet portal that can be used as a calendar, phone directory, and much more. It is available as an open-source and commercial solution. We focused our analysis exclusively on the open-source version and detected several critical vulnerabilities that can be used to execute PHP code on the target system without any form of authentication.

Serendipity 2.0.3: From File Upload to Code Execution

8 min read 7 Dec 2016 by Hendrik Buchwald
Serendipity is an easy to maintain blog engine. There are a lot of plugins that can be used to extend the functionality, this article will focus on its core though. With close to 125,000 lines it is a medium-sized web application. In this post, we will show how attackers can bypass existing security mechanisms which can lead to remote code execution attacks.

Expression Engine 3.4.2: Code Reuse Attack

9 min read 5 Dec 2016 by Hendrik Buchwald
Expression Engine is a popular general purpose content management system that is used by thousands of individuals, organizations, and companies around the world. In this post, we will examine a code reuse vulnerability that leads to remote code execution. This vulnerability type allows an attacker to partly control the applications logic and to chain existing code fragements.

FreePBX 13: From Cross-Site Scripting to Remote Command Execution

11 min read 1 Dec 2016 by Hendrik Buchwald
FreePBX is a web-based graphical user interface that helps users to manage voice-over-IP services. With over one million production systems using FreePBX worldwide it is the most widely deployed open-source PBX (Private Branch Exchange) platform. Since FreePBX is written completely in PHP, we decided to throw it into our code analysis tool RIPS. The results were surprising…