GitHub Security Advisory: GHSA-f7cq-gvh6-qr25
Package: github.com/ctfer-io/monitoring (GO)
Severity: HIGH (CVSS 9.8)
CWE: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
Vulnerable versions: < 0.2.2
Patched in: 0.2.2

Summary: Monitoring is vulnerable to Archive Slip due to missing checks in sanitization

Details:
The `sanitizeArchivePath` function in `pkg/extract/extract.go` (lines 248–254) is vulnerable to a path traversal bypass due to a missing trailing path separator in the `strings.HasPrefix` check. A crafted tar archive can write files outside the intended destination directory when using the `extractor` CLI tool or the `extract.DumpOTelCollector` library function.

## Vulnerable Code

File: `pkg/extract/extract.go`, lines 248–254

```go
func sanitizeArchivePath(d, t string) (v string, err error) {
    v = filepath.Join(d, t)
    if strings.HasPrefix(v, filepath.Clean(d)) {   // ← missing trailing separator
        return v, nil
    }
    return "", fmt.Errorf("filepath is tainted: %s", t)
}
```

The function is called at line 219 inside `untar`, which is invoked by `copyFromPod` (line 205) during the Cold Extract data dump workflow.

## Root Cause

`strings.HasPrefix(v, filepath.Clean(d))` does not append a trailing `/` to the directory prefix, causing a **directory name prefix collision**. If the destination is `/home/user/extract-output` and a tar entry is named `../extract-outputevil/pwned`, the joined path `/home/user/extract-outputevil/pwned` passes the prefix check — it starts with `/home/user/extract-output` — even though it is entirely outside the intended directory.

## Steps to Reproduce

1. **Deploy the monitoring stack** with `ColdExtract: true`. The OTEL Collector begins writing signal data (`otel_traces`, `otel_metrics`, `otel_logs`) to the shared PVC.

2. **Place the PoC tar on the PVC.** Any pod with write access to the `ReadWriteMany` PVC (or the compromised OTEL Collector itself) copies a `poc-path-traversal.tar` into the `/data/collector` mount path. The archive contains three real-looking OTLP telemetry files alongside two crafted entries with path-traversal names.

3. **Run the extractor against the namespace:**

   ```
   extractor \
     --namespace monitoring \
     --pvc-name <signals-pvc-name> \
     --directory /home/user/extract-output
   ```

4. **Observe the bypass.** `untar` processes the tar stream. For the malicious entries:

   ```
   // entry name: ../extract-outputevil/poc-proof.txt
   filepath.Join("/home/user/extract-output", "../extract-outputevil/poc-proof.txt")
     => "/home/user/extract-outputevil/poc-proof.txt"

   strings.HasPrefix("/home/user/extract-outputevil/poc-proof.txt",
                     "/home/user/extract-output")
     => true   // BUG: prefix collision; file lands OUTSIDE target dir
   ```

   Both malicious entries are written outside `/home/user/extract-output/`. The three legitimate OTLP files land correctly inside it.

## Impact

Successful exploitation gives an attacker arbitrary file write on the machine running the extractor. Real-world primitives include:

- Overwriting `~/.bashrc` / `~/.zshrc` / `~/.profile` for RCE on next shell login
- Appending to `~/.ssh/authorized_keys` for persistent SSH backdoor
- Dropping a malicious entry into `~/.kube/config` to hijack cluster access
- Wr