Breaking

VMware NSX-T MITM Vulnerability (CVE-2020-3993)

NSX-T is a Software-Defined-Networking (SDN) solution of VMware which, as its basic functionality, supports spanning logical networks across VMs on distributed ESXi and KVM hypervisors. The central controller of the SDN is the NSX-T Manager Cluster which is responsible for deploying the network configurations to the hypervisor hosts.

This summer, I looked into the mechanism which is used to add new KVM hypervisor nodes to the SDN via the NSX-T Manager. By tracing what happens on the KVM host, I discovered that the KVM hypervisor got instructed to download the NSX-T software packages from the NSX-T Manager via unencrypted HTTP and install them without any verification. This enables a Man-in-the-Middle (MITM) attacker on the network path to replace the downloaded packages with malicious ones and compromise the KVM hosts.

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Misc

XSS Vulnerability in Froala WYSIWYG HTML Editor

Recently, I had a brief look at the Froala WYSIWYG HTML Editor (v3.2.0) as there was a post about it on the Full Disclosure mailing list.

When targeting a HTML Editor, I guess one of the first things that everybody does is to check for XSS vulnerabilities. So I tried the usual XSS payloads (a great resource for XSS payloads is the XSS cheat sheet by PortSwigger) within the editor’s code view, but did not have much luck with the common payloads as they were filtered. However, using the HTML object tag, it was possible to trigger an XSS.

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Misc

Microsoft Office Telemetry: Report Release

The German Federal Office for Information Security (orig., ger., Bundesamt für Sicherheit in der Informationstechnik – BSI) has published our report on Microsoft Office Telemetry.

Microsoft has released a set of privacy settings for Office, one of which enables users to configure the type and amount of diagnostic (i.e., telemetry) data that Office may send to Microsoft. When deployed, it is available in the form of a group policy setting. It allows users to configure one of the following diagnostic data levels: required, optional, or neither.  The report we produced:

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Misc

Forklift <=3.3.9 and <=3.4 Local Privilege Escalations on macOS (CVE-2020-15349/CVE-2020-27192)

I have started to have a look at my local installed helpers on macOS. These helpers are used as an interface for applications to perform privileged operations on the system. Thus, it is quite a nice attack surface to search for Local Privilege Escalations.

Forklift is an advanced dual pane file manager for macOS. It is well known under macOS power users.

As part of my investigation I identified vulnerabilities in Forklift allowing local privilege escalation.

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Building

Reversing C++ Without Getting a Heart Attack – DEvirtualize VIrtual Calls With Devi

TLDR: This blogpost presents devi, a tool that can help you devirtualize virtual calls in C++ binaries. It uses Frida to trace the execution of a binary and uncover the call sources and destinations of virtual calls. The collected information can then be viewed in IDA Pro, Binary Ninja, or Ghidra. The plugin adds the respective control-flow edges allowing further analysis (using different plugins) or simply providing more comfort when analyzing C++ binaries.

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Misc

Apps on Prescription?! – Perspectives on Digital Health Applications (DiGA)

Some time ago, we carried out an evaluation of the Digital Health Applications Ordinance (Digitale-Gesundheitsanwendungen-Verordnung, DiGAV) for the Federal Chamber of Psychotherapists in Germany (Bundespsychotherapeutenkammer, BPtK) focusing on the security of digital health applications, often referred to as apps on prescription.

The audit was intended to determine to which extent security guidelines, security objectives, and best practices are adhered to by the requirements formulated by the ordinance, thus enabling the foundations to securely operate digital health applications. The main subject of the examination is whether requirements, including procedural requirements defined in the ordinance are sufficient to ensure security of digital health applications. The examination has shown that the requirements can be seen as positive. However, in order to be able to make reliable statements about the IT security of digital healthcare applications, further details and mechanisms should be clarified within the ordinance, which I would like to present in the following.

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Misc

OpenSIS Vulnerabilities

OpenSIS is an open source student information system. Recently, it was affected by several vulnerabilities such as SQL injections, local file inclusions and incorrect access controls (CVE-2020-13380, CVE-2020-13381, CVE-2020-13382, CVE-2020-13383). That is why I got interested and also had a quick look at the application.

As part of this investigation, I discovered two vulnerabilities, an XSS vulnerability (CVE-2020-27409) in the file SideForStudent.php that got quickly fixed after being reported (see commit edca085 for the details; the commit is included in release v7.5) and some incorrect (i.e. non-existent) access controls for the password change functionality (CVE-2020-27408). In this blog post, I would like to focus on the second vulnerability and describe the tedious disclosure process that – in the end – lead to nothing but the implementation of some ineffective obfuscation mechanism.

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Breaking

Vulnerabilities in GNU Readline Fixed

Recently I discovered some vulnerabilities in GNU Readline. These bugs have been fixed in GNU Readline version 8.1.

The case of identifying the vulnerabilities was rather interesting. I wanted to fuzz another program and wrote a quick harness to test if my setup works. This test harness used GNU Readline to read input from stdin and passed the data along to the function under test. I left the fuzzer running while I started to improve the harness (which would also mean getting rid of GNU Readline as it is relatively slow for the use-case at hand). However, AFL showed the first crashes and upon inspection, the vulnerabilities where not in the code I actually wanted to fuzz but in my systems GNU Readline.

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Building

Doing it Server-Side with CypherDog 4.0

Arrroooo… Bloodhound Crew!! Heard the news? CypherDog 4.0 is out and it’s full of new features…

Now a couple of you might be thinking “Hey there, wait a minute… didn’t CypherDog 3.0 come out not that long ago..??”, and I am happy to see some of you are paying attention…
Indeed, when Bloodhound 3 came out, I quickly updated CypherDog 2 to CypherDog 3 to be compatible with it.
But Bloodhound 3 is compatible with neo4j 3 and 4, however the neo4j REST API has been deprecated in neo4j 4 and CypherDog 3 relied on it.
Long story short, CypherDog 4.0 is a full rewrite compatible with the new neo4j 4 HTTP API, and since I was refactoring the whole thing, I added some cool new features to the tool.
The idea was to be able to do more with less keystrokes, and to do it server-side…
And so I made a meme.

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Breaking

ERNW White Paper 69 – Safety Impact of Vulnerabilities in Insulin Pumps

With this blog post I am pleased to announce the publication of a new ERNW White Paper [1]. The paper is about severe vulnerabilities in an insulin pump we assessed during project ManiMed and we are proud to publish this subset of the results today.

Manipulating Medical Devices

The German Federal Office for Information Security (BSI), in its role as the Federal Cyber Security Authority in Germany, aims to sensitize manufacturers and the public regarding security risks of networked medical devices. In response to the often fatal security reports and press releases of networked medical devices, the BSI initiated the project Manipulation of Medical Devices (ManiMed) in 2019. In this project, a security analysis of selected products is carried out through security assessments. In the context of this project, severe vulnerabilities were identified during the assessment of the DANA Diabecare RS system.

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