## https://sploitus.com/exploit?id=E6B39DC4-9A83-503E-827F-03E07D5AD7D4
# CVE-2025-2783: Google Chrome Mojo Sandbox Escape
**CVSS Score:** 8.3 (High)
**Discovered by:** Kaspersky
**Status:** Actively exploited in the wild (espionage campaigns)
## Overview
CVE-2025-2783 is a Windows-specific privilege escalation vulnerability in Google Chrome's Mojo Interprocess Communication (IPC) framework. It allows a compromised renderer process to escape the Chrome sandbox by exploiting incorrect handle handling in the Mojo message-passing layer.
This CVE was identified as part of an active exploitation chain targeting journalists and opposition figures. The sandbox escape was paired with a separate renderer remote code execution (RCE) vulnerability to achieve full system compromise.
## Technical Details
The vulnerability lies in the Mojo IPC channel's handling of Windows HANDLE objects during message serialization and deserialization. Specifically:
- **Handle Confusion:** The Mojo broker on Windows incorrectly validates and transfers handles between the privileged browser process and sandboxed renderer processes. A crafted IPC message can cause the broker to duplicate a handle into the renderer process with unintended access rights.
- **Missing Access Check:** The broker fails to verify that the renderer is permitted to receive the duplicated handle, effectively allowing any compromised renderer process to request and obtain a handle to sensitive kernel objects.
- **Elevation of Privilege:** Once a malicious renderer obtains the improperly duplicated handle, it can leverage it to perform privileged operations (e.g., process creation, file system access) outside the sandbox boundary.
The exploit flow:
1. Attacker compromises renderer via RCE (separate vulnerability)
2. Renderer sends a crafted Mojo IPC message to the browser process
3. Browser process's Mojo broker improperly duplicates a privileged handle
4. Renderer receives the handle and uses it to escape the sandbox
5. Full system access achieved
## Affected Versions
- **Google Chrome:** **WARNING:** This is for authorized security research and educational purposes only. Unauthorized testing against live systems is illegal.
### Prerequisites
- Windows 10/11 (fully patched)
- Google Chrome 134.0.6998.176 or earlier
- Python 3.8+
- Debug symbols enabled for Chrome (`--enable-logging --v=1`)
### Steps
1. Generate the malicious payload file using `exploit.py`
2. Serve the payload via a local HTTP server or host it on a controlled domain
3. Open Chrome and navigate to the page hosting the payload
4. The renderer process will execute the crafted Mojo IPC message
5. Verify sandbox escape by checking process tree (renderer spawns child outside sandbox)
## Proof of Concept
The accompanying `exploit.py` demonstrates the concept of crafting a malicious Mojo IPC message that triggers the handle confusion. It does **not** contain a working exploit against patched browsers and is intended solely for educational understanding of the vulnerability class.
```python
# See exploit.py for the full demonstration
```
## Mitigation
- **Update Chrome:** Upgrade to Chrome 134.0.6998.177 or later
- **Enterprise:** Deploy the update via Group Policy or MDM immediately
- **EDR Detection:** Monitor for anomalous Mojo IPC message patterns and unexpected handle duplication events
- **Defense in Depth:** Run Chrome with additional sandboxing layers (e.g., AppContainer, restricted token) and endpoint detection
The official fix addresses the missing access check in the Mojo broker's handle transfer logic. Specifically, the broker now validates that the requesting process has the necessary privileges before duplicating a handle.
## References
- [Kaspersky Threat Research - Operation ForumTroll](https://www.kaspersky.com/blog/forumtroll-apt-campaign/)
- [Google Chrome Releases - Stable Channel Update](https://chromereleases.googleblog.com/2025/03/stable-channel-update-for-desktop.html)
- [NVD - CVE-2025-2783](https://nvd.nist.gov/vuln/detail/CVE-2025-2783)
- [Chromium Mojo Documentation](https://chromium.googlesource.com/chromium/src/+/main/mojo/README.md)
- [Mitre ATT&CK - T1068: Exploitation for Privilege Escalation](https://attack.mitre.org/techniques/T1068/)