PayPal Remote Code Execution Vulnerability Patched


So this is a big one, and thankfully this PayPal Remote Code Execution Vulnerability was discovered by security researchers and not the bad guys. Although there’s no way for us to know if someone has been using this to siphon data out of PayPal for some time before the whitehats found it.

PayPal Remote Code Execution Vulnerability Patched

It’s a roundabout bug that turns out serious, and why I tell developers don’t mess with serialised data – it’s ugly. In this case object deserialisation in Java basically allowed for remote command execution on PayPal servers.

Independent security researcher Michael Stepankin has reported a since-patched remote code execution hole in Paypal that could have allowed attackers to hijack production systems.

The critical vulnerability affecting manager.paypal.com revealed overnight was reported 13 December and patched soon after disclosure.

It allowed Stepankin to execute arbitrary shell commands on PayPal web servers through Java object deserialisation opening access to production databases.

“I immediately reported this bug to PayPal security team and it was quickly fixed after that,” Stepankin says

“While security testing of manager.paypal.com, my attention was attracted by unusual post form parameter “oldFormData” that looks like a complex object after base64 decoding.


It was reported responsibly and fixed fairly quickly, PayPal does have quite a good record of reacting in a timely fashion.

You can read the original blog post here: PayPal Remote Code Execution Vulnerability

“After some research I realised that it’s a Java serialised object without any signature handled by the application [which] means that you can send serialised object of any existing class to a server and ‘readObject’ or ‘readResolve’ method of that class will be called.”

Attackers would need to follow the technique disclosed by FoxGlove Security to gain remote code execution.

Stepankin says he used their ‘ysoserial’ payload generation tool in his attack.

PayPal handed out US$5000 for the bug even though it was a duplicate of a report sent in two days prior by researcher Mark Litchfield. Most bug bounty operators do not pay for duplicates making the payment unusual.

Strangely enough it seems to like two researchers found the same bug within days of each other independently. So PayPal paid them both a bounty, which is very rare – and pretty cool IMHO.

You can read about what Mark Litchfield got upto in December here – My $50k Personal Challenge – Results

Pretty good earnings for a months work, although I might imagine he’s had a fair number of those bugs in pocket for a while.

Source: The Register

Posted in: Exploits/Vulnerabilities, Web Hacking

, ,


Latest Posts:


GKE Auditor - Detect Google Kubernetes Engine Misconfigurations GKE Auditor – Detect Google Kubernetes Engine Misconfigurations
GKE Auditor is a Java-based tool to detect Google Kubernetes Engine misconfigurations, it aims to help security & dev teams streamline the configuration process
zANTI - Android Wireless Hacking Tool Free Download zANTI – Android Wireless Hacking Tool Free Download
zANTI is an Android Wireless Hacking Tool that functions as a mobile penetration testing toolkit that lets you assess the risk level of a network using mobile.
HELK - Open Source Threat Hunting Platform HELK – Open Source Threat Hunting Platform
The Hunting ELK or simply the HELK is an Open-Source Threat Hunting Platform with advanced analytics capabilities such as SQL declarative language, graphing etc
trape - OSINT Analysis Tool For People Tracking Trape – OSINT Analysis Tool For People Tracking
Trape is an OSINT analysis tool, which allows people to track and execute intelligent social engineering attacks in real-time.
Fuzzilli - JavaScript Engine Fuzzing Library Fuzzilli – JavaScript Engine Fuzzing Library
Fuzzilii is a JavaScript engine fuzzing library, it's a coverage-guided fuzzer for dynamic language interpreters based on a custom intermediate language.
OWASP APICheck - HTTP API DevSecOps Toolset OWASP APICheck – HTTP API DevSecOps Toolset
APICheck is an HTTP API DevSecOps toolset, it integrates existing tools, creates execution chains easily and is designed for integration with 3rd parties.


Comments are closed.