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All #Advisory Articles

The Journey of Bypassing Ubuntu’s Unprivileged Namespace Restriction

Pumpkin

 2025-06-26

Recently, Ubuntu introduced sandbox mechanisms to reduce the attack surface, and they seemed unbreakable. However, after carrying out in-depth research, we found that the implementation contained some issues, and bypassing it was not as difficult as expected. This post will explain how we began our research at the kernel level and discovered a bypass method. We will also share some interesting stories from the process.

Confusion Attacks: Exploiting Hidden Semantic Ambiguity in Apache HTTP Server!

Orange Tsai

 2024-08-09

This article explores architectural issues within the Apache HTTP Server, highlighting several technical debts within Httpd, including 3 types of Confusion Attacks, 9 new vulnerabilities, 20 exploitation techniques, and over 30 case studies. The content includes, but is not limited to: 1. How a single ? can bypass Httpd's built-in access control and authentication. 2. How unsafe RewriteRules can escape the Web Root and access the entire filesystem. 3. How to leverage a piece of code from 1996 to transform an XSS into RCE.

How I Hacked Facebook Again! Unauthenticated RCE on MobileIron MDM

Orange Tsai

 2020-09-12

This post is about my research this March, which talks about how I found vulnerabilities on a leading Mobile Device Management product and bypassed several limitations to achieve unauthenticated RCE. All the vulnerabilities have been reported to the vendor and got fixed in June. After that, we kept monitoring large corporations to track the overall fixing progress and then found that Facebook didn't keep up with the patch for more than 2 weeks, so we dropped a shell on Facebook and reported to their Bug Bounty program!

Hacking Jenkins Part 2 - Abusing Meta Programming for Unauthenticated RCE!(EN)

Orange Tsai

 2019-02-19

After Jenkins released the [Security Advisory](https://jenkins.io/security/advisory/2018-12-05/#SECURITY-595) and fixed the dynamic routing vulnerability on 2018-12-05, I started to organize my notes in order to write this Hacking Jenkins series. While reviewing notes, I found another exploitation way on a gadget that I failed to exploit before! Therefore, the part two is the story for that! This is also one of my favorite exploits and is really worth reading :)

Hacking Jenkins Part 1 - Play with Dynamic Routing (EN)

Orange Tsai

 2019-01-16

This article is mainly about a brief security review on Jenkins in the last year. During this review, we found 5 vulnerabilities including: CVE-2018-1999002(Arbitrary file read vulnerability), CVE-2018-1000600(CSRF and missing permission checks in GitHub Plugin), CVE-2018-1999046(Unauthorized users could access agent logs), CVE-2018-1000861(Code execution through crafted URLs), CVE-2019-pending(Sandbox Bypass in Script Security and Pipeline Plugins)

Exim Off-by-one RCE: Exploiting CVE-2018-6789 with Fully Mitigations Bypassing

Meh

 2018-03-06

We reported an overflow vulnerability in the base64 decode function of Exim on 5 February, 2018, identified as CVE-2018-6789. This bug exists since the first commit of exim, hence ALL versions are affected. According to our research, it can be leveraged to gain Pre-auth Remote Code Execution and at least 400k servers are at risk. Patched version 4.90.1 is already released and we suggest to upgrade exim immediately.

Sandstorm Security Review

Shaolin

 2018-01-26

In order to leverage the vulnerabilities, we put part of efforts into review of Sandstorm's source codes, and tried to escape the sandbox to impact the whole server...

Road to Exim RCE - Abusing Unsafe Memory Allocator in the Most Popular MTA

Meh

 2017-12-11

On 23 November, 2017, we reported two vulnerabilities to Exim. These bugs exist in the SMTP daemon and attackers do not need to be authenticated, including CVE-2017-16943 for a use-after-free (UAF) vulnerability, which leads to Remote Code Execution (RCE); and CVE-2017-16944 for a Denial-of-Service (DoS) vulnerability.

Advisory: Accellion File Transfer Appliance Vulnerability

Orange Tsai

 2016-09-22

According to a public data reconnaissance, there are currently 1,217 FTA servers online around the world, most of which are located in the US, followed by Canada, Australia, UK, and Singapore. Determine from the domain name and SSL Certificate of these servers, FTA is widely used by governmental bodies, educational institutions, enterprises, including several well-known brands.