Compass Security Blog

Offensive Defense

bRPC-Web: A Burp Suite Extension for gRPC-Web

The gRPC framework, and by extension gRPC-Web, is based on a binary data serialization format. This poses a challenge for penetration testers when intercepting browser to server communication with tools such as Burp Suite.

This project was initially started after we unexpectedly encountered gRPC-Web during a penetration test a few years ago. It is important to have adequate tooling available when this technology appears. Today, we are releasing our Burp Suite extension bRPC-Web in the hope that it will prove useful to others during their assessments.

Continue reading

SharePoint: Collaboration vs. XSS

SharePoint is a very popular browser-based collaboration and content management platform. Due to its high complexity, proprietary technology and confusing terminology it is often perceived as a black-box that IT and security professionals do not feel very comfortable with. These days, web security topics are well understood by many security professionals, penetration testers and vendors. But what […]

Continue reading

SharePoint: How to collaborate with external parties?

Opening up an internal SharePoint farm to the Internet in order to share resources with external parties might seem a good idea, because it helps avoiding expensive infrastructure changes. However, in terms of security, this is not recommended because it does not sufficiently protect internal resources from external threats. The protection of internal resources hinges […]

Continue reading

Wrap-up: Hack-Lab 2017#1

What is a Hack-Lab? Compass Security provides a monthly playful occasion for the security analysts to get-together and try to hack new devices, dive into current technologies and share their skills with their fellows. This also includes the improvement of internal tools, the research of newly identified publicly known attacks, and security analysis of hardware […]

Continue reading

Secure XML Parser Configuration

Most XML parsers are vulnerable for XML external entitiy attacks (XXE) by default. So what’s your mitigation? The easiest way to prevent XXE is to disallow the Doctype declaration completely: import java.io.File; import org.jdom.Document; import org.jdom.JDOMException; import org.jdom.input.SAXBuilder; public class XEE_Disallow_Doctype_Decl { public static void main(String[] args) { String element= null; SAXBuilder objBuilder = null; […]

Continue reading

AntiSamy to face XSS and XXE

The community hosts a neat little project called AntiSamy[1] which lends its name from the well known MySpace worm[2] and which comes in handy when trying to mitigate Cross-site Scripting[3] attacks. Whereby XSS is sometimes hard to mitigate when business is asking for HTML formatting in user supplied inputs. At that point, AntiSamy might become […]

Continue reading