Decrypting Eazfuscator.NET encrypted symbol names

There are many obfuscators for different languages, and some of those offer reversible options for easier field debugging. Eazfuscator.NET is one of these and with a bit of reverse engineering, whole files can be restored with the original symbols once you have the password. In our case, the developer left...

5 minute read

Drop-by-Drop: Bleeding through libvips

During a recent engagement we encountered a quite common web application feature: profile image uploads. One of the tools we used for the tests was the UploadScanner Burp Suite extension, that reported no vulnerabilities. However, we noticed that the profile picture of our test user showed seemingly random pixels. This...

8 minute read

Our take on social engineering

Like many other offensive IT security companies, we also offer social engineering assessments. And like in other areas of our portfolio, we try to steer client needs in a way that they order something that actually matters. This blog post summarizes what we experienced and how we see things in...

9 minute read

The curious case of encrypted URL parameters

As intra-app URLs used in web applications are generated and parsed by the same code base, there’s no external force pushing developers towards using a human-readable form of serialization. Sure, it’s easier to do debugging and development, but that’s why I used the word “external”. Many frameworks use custom encodings,...

6 minute read

Snow cannon vs. unique snowflakes — testing registration forms

Many of the web application tests we conducted had a registration form in the scope. In such cases, there’s usually a field that needs to be unique for each invocation, sometimes called username, in other cases, the e-mail address is used as such. However, launching the Scanner or Intruder of...

3 minute read

Bare Knuckled Antivirus Breaking

Endpoint security products provide an attractive target for attackers because of their widespread use and high-privileged access to system resources. Researchers have already demonstrated the risks of complex input parsing with unmanaged code and even sloppy implementation of client- and server-side components of these products. While these attacks are still...

5 minute read

Emulating custom crytography with ripr

Custom cryptography and obfuscation are recurring patterns that we encounter during our engagements and research projects. Our experience shows that despite industry best practices and long history of failures these constructs are not getting fixed without clear demonstration of their flaws. Most of the time demonstration requires instrumenting the original...

6 minute read

Conditional DDE

Here’s a little trick we’d like to share in the end-of-year rush: DDE is the new black, malware authors quickly adopted the technique and so did pentesters and red teams in order to simulate the latest attacks. According to our experience trivial DDE payloads (like fully readable PowerShell scripts) slip...

2 minute read