Bug Bytes #105 – Playing with Spring Boot Actuators, recon API sources, JS encryption & A heaps of writeups

By Anna Hammond

January 13, 2021

Bug Bytes is a weekly newsletter curated by members of the bug bounty community. The first series is curated by Mariem, better known as PentesterLand. Every week, she keeps us up to date with a comprehensive list of write-ups, tools, tutorials and resources.

This issue covers the week from 03 to 10 of January.

Intigriti News

The cost of poor software quality, Zyxel backdoor & Yet another T-Mobile data breach

Our favorite 5 hacking items

1. Tool of the week


Microsubs is a new tool for interacting with recon APIs. @codingo_ presented it at BSides Brisbane. I was waiting for the talk to become public to talk about it, but it’s been a month already.

It is interesting to play with Microsubs if you’re interested in assets enumeration and understanding how API sources work by querying them directly. One particular use case is when different recon tools give unique results each and you want to use their sources directly instead of using all tools.

2. Writeups of the week

Exploiting Application-Level Profile Semantics (APLS)
Achieving Remote Code Execution By Exploiting Variable Check Feature
Stealing Your Private YouTube Videos, One Frame at a Time (Google, $5,000)
Create post on any Facebook page (Facebook, $30,000)
A ‘Novel’ Way to Bypass Executable Signature Checks with Electron

I know, FIVE writeups of the week is a lot, but they each have something different to teach.

@niemand_sec’s writeup shows how to identify and exploit APLS, a data format worth learning about in case you encounter it in Web app tests.

@ShawarkOFFICIAL wrote about a remote code execution via file upload. The interesting part is that Python files uploaded are not executed directly but other endpoints process them, which lead to blind RCE (so, a sort of Out of Band unrestricted file upload).

The following two writeups by @Pouyadarabi and @xdavidhu are all about IDOR, simple bugs (doesn’t mean easy to find!) with incredible impacts.

The last writeup is about exploiting Electron’s update process to get local privilege escalation. This is a great piece for anyone interested in the security of Electron or desktop applications.

3. Article of the week

Remote Code Execution in Three Acts: Chaining Exposed Actuators and H2 Database Aliases in Spring Boot 2 & Sample app

This is great research on exploiting exposed Spring Boot Actuators. @spaceraccoonsec starts with exposed /actuator/env and /actuator/restart endpoints and chains them with H2 database aliases, a feature of H2 Database Engine that makes it possible to run arbitrary SQL queries. This, combined with some WAF bypass-fu results in arbitrary command injection and a very informative writeup.

If you’d like a challenge, start with the sample app and try to craft an exploit yourself before reading the article.

4. News of the week

Top 10 web hacking techniques of 2020 – nominations open

It’s time to vote for your favorite Web hacking techniques of 2020! Most importantly, it is a good occasion to get acquainted with excellent research you might have missed last year.

5. Tutorial of the week

Client Side Encryption Bypass Part-1 & JavaScript Debugging Vulnerable Lab

This is the first article of a 3-parts series on breaking and bypassing JavaScript encryption when doing Web app testing. See how @sameer_bhatt does it using DevTools, practice on the provided vulnerable lab, and if you still want more there is also this related talk.

Other amazing things we stumbled upon this week



Webinars & Webcasts



Medium to advanced

Beginners corner


Challenge writeups

Pentest writeups

Responsible(ish) disclosure writeups

Bug bounty writeups

See more writeups on The list of bug bounty writeups.


  • Open url redirect payload generator

  • reconftw: Simple Bash script for full recon

  • s3cario: Python3 tool for testing AWS S3 buckets (based on S3Cruze)

  • takeover: A tool for testing subdomain takeover possibilities at a mass scale (similar to the discontinued SubOver)

  • fcm_server_key: Python tool to extract & validate google fcm server keys from apks

  • CISCO CVE-2020-3452 Scanner & Exploiter

  • EarlyBird: A sensitive data detection tool (in Go) capable of scanning source code repositories for clear text password violations, PII, outdated cryptography methods, key files and more

  • Pup: Go tool for parsing HTML at the command line

  • Ligolo: Reverse Tunneling made easy for pentesters, by pentesters

Misc. pentest & bug bounty resources


Bug bounty & Pentest news

Non technical

Tweeted this week

We created a collection of our favorite pentest & bug bounty related tweets shared this past week. You’re welcome to read them directly on Twitter: Tweets from 01/01/2021 to 01/03/2021.

You may also like