# GHSA-hqmp-g7ph-x543: TunnelVision - decloaking VPNs using DHCP

> Attackers can bypass VPN encryption by injecting routing entries via DHCP option 121, redirecting traffic to the local network.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 27 Dec 2024

## What is GHSA-hqmp-g7ph-x543?

GHSA-hqmp-g7ph-x543 is a vulnerability in quincy, published on 27 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

A new decloaking technique for nearly all VPN implementations has been found, which allows attackers to inject entries into the routing tables of unsuspecting victims using DHCP option 121. This allows attackers to redirect traffic, which is supposed to be sent encrypted over the VPN, through the physical interface handling DHCP for the network the victim's computer is connected to, effectively bypassing the VPN connection.

### Impact
All users are potentially affected, as this attack vector can be used against _any_ VPN implementation without mitigations in place.

### Patches
Currently, there are no existing mitigations employed by Quincy.

### Workarounds
Disabling DHCP option 121 in the DHCP client is a potential workaround, as it prevents this kind of attack.

### References
https://www.leviathansecurity.com/blog/tunnelvision

## Which versions are affected by GHSA-hqmp-g7ph-x543?

2 open source packages ship an affected version, including quincy.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `quincy` | crates.io | All versions to 0.13.0 | None |
| `quincy` | crates.io | All versions to 0.13.0 | None |

## How do I fix GHSA-hqmp-g7ph-x543?

No fix has been published for GHSA-hqmp-g7ph-x543 yet. Limit exposure of the affected software until one is available.

## Is GHSA-hqmp-g7ph-x543 being exploited?

There is no known exploitation of GHSA-hqmp-g7ph-x543 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for GHSA-hqmp-g7ph-x543 and fix it if it is affected.

What it is: GHSA-hqmp-g7ph-x543 is a vulnerability in quincy, published on 27 Dec 2024. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of GHSA-hqmp-g7ph-x543 in the wild and no public exploit code.

Affected packages and fixed versions:
- quincy (crates.io): affected all versions up to 0.13.0; no fix listed
- quincy (crates.io): affected all versions up to 0.13.0; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/GHSA-hqmp-g7ph-x543/ (Markdown: https://insights.sbomify.com/GHSA-hqmp-g7ph-x543/index.md)
```

## Sources

- OSV: https://osv.dev/vulnerability/GHSA-hqmp-g7ph-x543

---
From sbomify Insights: https://insights.sbomify.com/GHSA-hqmp-g7ph-x543/
Summaries are generated and may contain mistakes; the official description above is the record.