XXE information disclosure in ClamAV DMG file parser

This repository is a small standalone proof-of-concept exploit for CVE-2023-20052 in ClamAV. It contains two files: a README with usage notes and one executable script, exploit.sh, which is the sole entry point. The script is not a scanner or detector; it automates creation of a malicious DMG file intended to exploit an XXE-style parsing issue in ClamAV's handling of DMG/plist metadata. The exploit flow is: prompt the operator for a target file path to read, clone the libdmg-hfsplus project from GitHub, build its dmg utility inside a Docker multi-stage build, generate a benign DMG from a small source directory, copy the resulting DMG out of the container, and then patch the DMG bytes using embedded Python. The Python code searches the DMG for an XML plist header, replaces it with a crafted DOCTYPE containing an external entity declaration pointing to file://<TARGET_FILE>, and modifies a blkx token to blkx&xxe; so the entity is referenced during parsing. The final output is exploit.dmg. Main capability: arbitrary local file read from the system running vulnerable ClamAV, if that system scans or parses the crafted DMG. The exploit does not include exfiltration, reverse shell, persistence, or remote command execution; it is focused on generating a malicious file artifact that triggers file disclosure during antivirus processing. Because it produces a working malicious payload but with a fixed/basic technique and no flexible delivery framework, the maturity is best classified as OPERATIONAL.

This repository provides a proof-of-concept (POC) exploit for CVE-2023-20052, an information leak vulnerability in the DMG file parser of ClamAV. The repository contains a Dockerfile that sets up an Ubuntu-based environment with all necessary tools to build and manipulate DMG files, including cloning and compiling the 'libdmg-hfsplus' utility. The README.md provides step-by-step instructions to create a malicious DMG file: a normal DMG is generated, then modified using 'bbe' to inject an XXE payload into the plist, referencing '/etc/passwd'. When this crafted DMG is scanned by ClamAV, the XXE is triggered, causing ClamAV to leak the contents of the targeted file. The exploit is local in nature, requiring the attacker to supply the malicious DMG to a system running ClamAV. The repository does not contain any direct exploit code, but provides the environment and commands necessary to generate the payload. No network C2 or remote endpoints are involved, but several URLs and file paths are fingerprintable from the Dockerfile and documentation.