# Vulnerability Verification Report

## 1. Summary
- **Vulnerability Type**: Command Injection / Blocklist Bypass (CWE-77)
- **Flagged Location**: src/tools/android/actions.rs:413-424
- **Vulnerability Description**: The Android device shell blocklist in `device_shell()` hardcodes exact flag orderings like `"rm -rf"` and `"rm -r"`. An attacker can bypass the blocklist by permuting command arguments (e.g., `rm -fr` or `rm -f -r`), allowing dangerous commands to execute on the connected Android device.

## 2. Analysis Logic

### Step 1: Examining the flagged sink at src/tools/android/actions.rs:408-446
I read the `device_shell` function which normalizes whitespace, checks a blocklist of dangerous substrings, checks for shell metacharacters, and then calls `adb.shell(cmd)` to execute the command on the Android device.

The blocklist is:
```rust
let blocked = [
    "rm -rf",
    "rm -r",
    "reboot",
    "factory_reset",
    "wipe",
    "format",
    "dd if=",
    "mkfs",
    "flash",
    "fastboot",
];
```

### Step 2: Tracing parameter origin via callers of device_shell()
I found `device_shell` is called from `src/tools/android/mod.rs:260`:
```rust
"shell" => {
    let cmd = args
        .get("command")
        .and_then(|v| v.as_str())
        .ok_or_else(|| ZeptoError::Tool("Missing 'command' parameter".into()))?;
    actions::device_shell(&self.adb, cmd).await
}
```

This is the `android` tool's `shell` action. The `args` come from the `Tool` trait's `execute` method, which receives JSON parameters from the LLM/agent. The `command` parameter is user-controllable.

### Step 3: Analyzing the blocklist bypass
The blocklist uses `.contains()` on the normalized command:
```rust
for pattern in &blocked {
    if lower.contains(pattern) {
        return Err(ZeptoError::Tool(format!(
            "Blocked dangerous command containing '{}'",
            pattern
        )));
    }
}
```

For a command like `rm -fr /data`:
- Normalized: `"rm -fr /data"`
- Does it contain `"rm -rf"`? No (flags are in different order)
- Does it contain `"rm -r"`? No (it's `"rm -fr"`)

For `rm -f -r /data`:
- Normalized: `"rm -f -r /data"`
- Does it contain `"rm -rf"`? No
- Does it contain `"rm -r"`? No (the substring is `"rm -f"`, not `"rm -r"`)

Both variants bypass the blocklist. The shell metacharacter check at lines 435-443 does not catch these because they do not use `;`, `|`, `` ` `` , `$`, `&`, or `\n`.

### Step 4: Confirming command execution sink
In `src/tools/android/adb.rs:77-79`:
```rust
pub async fn shell(&self, cmd: &str) -> Result<String> {
    self.run(&["shell", cmd]).await
}
```

This passes the command to `adb shell <cmd>`, which executes it on the Android device via a shell.

### Analysis Process
- Q1: Does user-controllable input reach a command/code execution sink? → YES (`src/tools/android/mod.rs:257-260`, `src/tools/android/actions.rs:445`)
- Q2: Is it code evaluation (eval/exec) with user data? → NO, it's process execution via ADB shell
- Q3: Is the command executed in array form without shell? → NO, `adb shell <cmd>` runs through the device shell
- Q4: Is the user input effectively sanitized? → NO, the blocklist can be bypassed via argument permutation (e.g., `"rm -fr"`, `"rm -f -r"`)
- Q5: Is the code in test/demo/dead/generated context? → NO, it's production code in the Android device control tool
- → Reached leaf: TRUE_POSITIVE

## 3. Verdict
**TRUE_POSITIVE**

**Key Evidence:**
- The `device_shell` blocklist hardcodes `"rm -rf"` and `"rm -r"` but `"rm -fr"` bypasses it because `"rm -fr".contains("rm -r")` is false (`src/tools/android/actions.rs:413-432`)
- The `command` parameter flows from the `android` tool's JSON arguments directly to `adb.shell(cmd)` with only an incomplete blocklist as protection (`src/tools/android/mod.rs:257-260`, `src/tools/android/adb.rs:77-79`)
- The dangerous metacharacter check at lines 435-443 does not prevent reordered flags because `;`, `|`, `` ` ``, `$`, `&`, and `\n` are not required to form a dangerous `rm` command

## 4. Remediation Suggestions
- Replace the substring-based blocklist with a robust allowlist or parser-based approach. Parse the command into tokens and check the command name against an allowlist of permitted commands.
- Alternatively, use a command parser (e.g., `shlex`-equivalent) to tokenize the command and check the executable and flags independently, rather than matching literal substrings.
- Consider removing the `shell` action entirely if it is not strictly necessary, as it provides a wide attack surface.
- If the `shell` action must remain, consider requiring explicit user approval for any shell command execution.
