提交 #855792: mosaxiv clawlet 0.2.10 Protection Mechanism Failure (CWE-693)

# Technical Details
A protection mechanism failure exists in the `(*Registry).exec` flow in `tools/tool_exec.go`, reached from `tools.Registry.Execute` in `tools/registry.go` and guarded by `guardExecCommand` in `tools/exec_guard.go` of clawlet.

The application fails to validate interpreter-wrapped payloads before passing the original command to `sh -lc`. The guard only checks the outer shell string and denylisted patterns, so an inline payload such as `python3 -c` can perform destructive actions that direct shell syntax like `rm -rf` would block.

# Vulnerable Code
File: `tools/exec_guard.go`, `tools/tool_exec.go`, `tools/registry.go`
Method: `guardExecCommand`, `(*Registry).exec`, `(*Registry).Execute`
Why: `guardExecCommand` inspects only the raw command text and does not unwrap or normalize inline interpreter payloads. After that check, `(*Registry).exec` still executes the original attacker-controlled string through `exec.CommandContext(..., "sh", "-lc", command)`.

# Reproduction
1. Prepare an affected clawlet checkout and a writable test workspace with `target.txt` inside it.
2. Invoke the real exported `exec(command: string)` path through `tools.Registry.Execute` using `python3 -c "__import__('os').remove('target.txt')"`.
3. Confirm the wrapped payload is accepted and `workspace/target.txt` is deleted, while a control payload such as `rm -rf target.txt` is blocked by the guard.

# Impact
- An attacker can bypass the intended command safety restrictions and run destructive interpreter logic.
- Workspace files can be deleted or modified under the privileges of the clawlet process.
- CI runners or developer environments can suffer artifact tampering or code modification.

• 来源: ⚠️ https://github.com/mosaxiv/clawlet/issues/12
• 用户: Eric-b (UID 96354)
• 提交: 2026-06-11 08時58分 (1 月前)
• 管理: 2026-07-13 18時57分 (1 month later)
• 状态: 已接受
• VulDB条目: 378121 [mosaxiv clawlet 直到 0.2.10 exec Safety Guard tools/tool_exec.go guardExecCommand 权限提升]
• 积分: 20