Spaceraccoon's Blog

InfoSec and White Hat Hacking

Rule Writing for CodeQL and Semgrep

One common perception is that it is easier to write rules for Semgrep than CodeQL. Having worked extensively with both of these static code analysis tools for about a year, I have some thoughts.

I Hope This Sticks: Analyzing ClipboardEvent Listeners for Stored XSS

When is copy-paste payloads not self-XSS? When it’s stored XSS. Recently, I reviewed a Zoom’s code to uncover an interesting attack vector.

Challendar: Creating a Challenge for The Infosecurity Challenge 2022

Although I do not actively participate in CTFs, I enjoy creating challenges for them as it forces me to learn by doing. Creating a good CTF challenge is an art, not a science. As the winner of last year’s $30k The InfoSecurity Challenge (TISC), I decided to contribute a challenge instead this year.

Exploiting Improper Validation of Amazon Simple Notification Service SigningCertUrl

Countless applications rely on Amazon Web Services’ Simple Notification Service for application-to-application communication such as webhooks and callbacks. To verify the authenticity of these messages, these projects use certificate-based signature validation based on the SigningCertURL value. Unfortunately, a loophole in official AWS SDKs allowed attackers to forge messages to all SNS HTTP subscribers.

You Have One New Appwntment: Exploiting iCalendar Properties in Enterprise Applications

First defined in 1998, the iCalendar standard remains ubiquitous in enterprise software. However, it did not account for modern security concerns and allowed vendors to create proprietary extensions that expanded the format’s attack surface. I demonstrate how flawed RFC implementations led to vulnerabilities in popular enterprise applications. Attackers can trigger exploits remotely with zero user interaction due to automatic parsing of event invitations. Furthermore, I explain how iCalendar’s integrations with the SMTP and CalDAV protocols enable multi-stage attacks. Despite attempts to secure these technologies separately, the interactions that arise from features such as emailed event reminders require a “full-stack” approach to calendar security. I conclude that developers should strengthen existing iCalendar standards in both design and implementation.