GuardDog: Unsanitized human-readable scan output allows terminal escape injection from malicious package content
# Summary
GuardDog includes attacker-controlled filenames, file locations, messages, and code snippets in its default human-readable output without escaping terminal control characters. A malicious package can therefore inject ANSI or OSC escape sequences into analyst terminals or CI logs.
# Description
The finding formatter stores file paths and snippets from scanned content:
```python
location = file_path + ":" + str(start_line)
finding = {
"location": location,
"code": code,
"message": result["extra"]["message"],
}
```
The human-readable reporter later prints these values directly:
```python
" * " + finding["message"] + " at " + finding["location"] + "\n " + _format_code_line_for_output(finding["code"])
```
No escaping is applied for control characters such as \x1b. A malicious package can therefore ship a filename like:
```text
evil\x1b[2J.py
```
or matched source lines containing terminal escapes, which survive into the final CLI output.
# Reproduction summary
1. Create a file whose name contains \x1b[2J.
2. Feed a semgrep-style result referencing that file into Analyzer._format_semgrep_response().
3. Render the result with HumanReadableReporter.print_scan_results().
4. The output string contains the raw escape bytes, which a terminal may interpret.
# Key code paths
guarddog/analyzer/analyzer.py:377-392guarddog/reporters/human_readable.py:36-42guarddog/reporters/human_readable.py:84-91
# Practical impact
This can be used to:
- clear or rewrite analyst terminal output
- inject misleading or spoofed log content in CI
- emit clickable OSC 8 hyperlinks or title changes in compatible terminals
# Prior public disclosure check
As of 2026-03-18, no matching public GitHub advisory, CVE, or public repo issue was found for this specific bug.
# Suggested fix
Escape or strip terminal control characters before rendering any attacker-controlled value in human-readable output. This should cover package names, file paths, messages, and code snippets.
