Dht11 Temp

• Outcome: Review
• Latest audit: Sep 10, 2026 · 8:10 PM UTC
• Version: 1.0.0

Overview

This DHT11 sensor skill is simple and not deceptive, but it asks users to run Python with sudo and includes a recurring privileged cron example without enough safeguards.

Review before installing. Prefer running this under least-privilege GPIO permissions instead of sudo, avoid the privileged cron example unless you harden the script path and scheduling, pin or otherwise trust the RPi.GPIO dependency, and be aware the current script may report temperature and humidity in the wrong order.

A.I.G

Vulnerability Patterns

• System Persistence: Installs backdoors, hooks, services, or scheduled tasks that survive the run
• Insecure Dependencies: Introduces malicious components through unsafe dependency sources
• Insecure Skill Coding Practices: Finds exploitable flaws such as hardcoded secrets or command injection
• Skill Instruction Hijacking: Alters the agent's session goals or safety constraints when the skill loads
• Agent Memory Poisoning: Writes attacker-controlled rules into memory that affect later sessions

Findings (3)

T06 · System Persistence

Error

• Location: SKILL.md:60
• Finding: Recurring Privileged Cron Execution Creates a Persistence and Privilege-Escalation Risk<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md:60-65` **Vulnerability Type**: `T06: System Persistence` **Risk Level**: High ### Vulnerable Code ```bash ## Example crontab entry # Read every 30 minutes */30 * * * * sudo python3 ~/scripts/dht/main.py >> /var/log/dht.log 2>&1 ``` ### Technical Analysis The documentation recommends configuring a cron entry that executes the sensor script every 30 minutes through `sudo`. This creates cross-session scheduled execution and exceeds the minimum privileges required for an on-demand temperature and humidity reading. The command executes a script located below a user's home directory. If the script or a parent directory is writable by a less-privileged user, replacing the script can turn the scheduled command into a privileged execution mechanism. Successful unattended execution depends on the host's `sudoers` configuration; if passwordless execution is not permitted, the task may fail instead. If passwordless execution is permitted, compromise of the referenced script can result in root-level command execution. The command also references `scripts/dht/main.py`, while the package contains `scripts/main.py`. This mismatch may lead users to create wrappers or copies at an unintended, insufficiently protected location. ### Attack Path 1. A user follows the documentation and installs the recurring cron entry. 2. The system permits unattended `sudo` execution for Python or the referenced command. 3. An attacker compromises the account, another process running as that account, or any writable component of the referenced path. 4. The attacker replaces `~/scripts/dht/main.py` with malicious Python code. 5. Cron reaches the next 30-minute interval and invokes the modified script through `sudo`. 6. The attacker's code executes with the privileges granted by the applicable `sudoers` rule, potentially including root. ### Impact Assessment If unattended `sudo` is available, exploitation may provide persisten ...[truncated 489 chars]
• Remediation: <![CDATA[ ## Remediation Suggestions - Remove the cron example unless continuous monitoring is an explicit part of the Skill's declared functionality. - Make any scheduling procedure clearly optional and explain its persistence and security implications. - Do not invoke the sensor reader through unrestricted `sudo`. Grant only the minimum GPIO device access required, such as through a dedicated group or narrowly scoped device permissions. - Run scheduled monitoring under a dedicated, unprivileged service account. - Reference an absolute path to a root-owned, non-user-writable script rather than a path beneath a user's home directory. - If elevated execution is unavoidable, use a narrowly scoped `sudoers` rule for a fixed root-owned executable; do not grant general Python execution. - Protect log files with restrictive ownership and permissions, and configure rotation. - Add execution time limits and overlap prevention to ensure a failed sensor read cannot accumulate scheduled processes. - Correct the documented path to match the packaged script location. ]]>

T08 · Insecure Dependencies

Warning

• Location: SKILL.md:23
• Finding: Unpinned Third-Party Dependency Installation<![CDATA[ ## Vulnerability Details **File Location**: `SKILL.md:23-26` **Vulnerability Type**: `T08: Insecure Dependencies` **Risk Level**: Medium ### Vulnerable Code ```bash # Install dependencies pip3 install RPi.GPIO ``` ### Technical Analysis The installation instruction retrieves `RPi.GPIO` without specifying a reviewed version, cryptographic hash, lock file, or trusted package index. Consequently, the package content installed by this command can change over time without any corresponding change to the audited Skill. Python packages can execute code during installation and whenever imported. A compromised package release, package-index account, or dependency resolution source could therefore introduce arbitrary code into the environment. Installing into the system Python environment also increases the scope of dependency conflicts and may affect other applications. This finding does not establish that `RPi.GPIO` is currently malicious. The risk comes from mutable, unverified dependency resolution. ### Attack Path 1. An attacker compromises the dependency's distribution account, publishing infrastructure, or configured package index. 2. The attacker publishes a malicious release that satisfies the unpinned package request. 3. A user follows the documented `pip3 install RPi.GPIO` command. 4. Pip retrieves and installs the attacker-controlled release. 5. Malicious installation logic executes, or malicious runtime logic executes when `scripts/main.py` imports `RPi.GPIO`. 6. The payload receives the privileges of the user performing installation or running the sensor script; the documentation's use of `sudo` may increase the runtime impact. ### Impact Assessment Successful exploitation could execute arbitrary code with the installing or invoking user's permissions. If the dependency is imported by a process run through `sudo`, malicious import-time behavior may execute with elevated privileges. Potential consequences include host compromise, modificat ...[truncated 72 chars]
• Remediation: <![CDATA[ ## Remediation Suggestions - Pin the dependency to a reviewed, known-good version. - Publish a requirements file containing cryptographic hashes and install it with `pip install --require-hashes`. - Explicitly use a trusted package index and avoid untrusted extra indexes. - Install dependencies in an isolated virtual environment rather than the system Python environment. - Review new dependency releases before updating the pin and hashes. - Where practical, use a distribution-maintained Raspberry Pi package with repository signature verification. - Avoid running the application as root so dependency compromise does not automatically provide elevated privileges. ]]>

T09 · Insecure Skill Coding Practices

Warning

• Location: scripts/main.py:38
• Finding: Unbounded GPIO Busy-Wait Loops Permit Local Denial of Service<![CDATA[ ## Vulnerability Details **File Location**: `scripts/main.py:38-44` **Vulnerability Type**: `T09: Insecure Skill Coding Practices` **Risk Level**: Medium ### Vulnerable Code ```python # Read data data = [] for i in range(40): while GPIO.input(DHT_PIN) == GPIO.LOW: pass start = time.time() while GPIO.input(DHT_PIN) == GPIO.HIGH: pass ``` ### Technical Analysis The two loops used to receive each of the 40 data bits do not enforce a deadline or iteration limit. If the GPIO input remains permanently low or high because of incorrect wiring, a disconnected or faulty sensor, an invalid pin selection, or a manipulated signal, execution remains in a tight loop indefinitely. Unlike the earlier response loops, these loops contain no sleep and no timeout counter. They can therefore consume a CPU core continuously. Because `GPIO.cleanup()` occurs only after all 40 bits have been read, an infinite loop also prevents normal GPIO cleanup. If the documented cron configuration is used, subsequent scheduled invocations can create additional stuck processes and increase resource consumption. ### Attack Path 1. The script starts reading the configured GPIO pin. 2. A faulty device, wiring problem, invalid pin selection, or deliberately controlled signal holds the pin at the level awaited by one of the busy-wait loops. 3. The corresponding loop never exits and continuously polls the GPIO input. 4. The process consumes CPU indefinitely and does not reach `GPIO.cleanup()`. 5. If recurring scheduling is configured without overlap protection, later executions start additional instances. 6. Repeated stuck processes progressively exhaust CPU, process-table, or related system resources. ### Impact Assessment Exploitation can cause local denial of service, sustained CPU consumption, accumulation of processes, and failure to release GPIO state cleanly. The immediate process receives no additional privileges through this flaw, but the availability ...[truncated 150 chars]
• Remediation: <![CDATA[ ## Remediation Suggestions - Add a monotonic-clock deadline to every GPIO transition loop. - Return a controlled sensor-read failure when a transition is not observed within the DHT11 protocol timing window. - Put GPIO setup and reading inside `try`/`finally` so `GPIO.cleanup()` runs after errors, interrupts, and timeouts. - Avoid unrestricted tight polling where possible; use short bounded waits appropriate to protocol timing. - Validate the selected GPIO number against an explicit set of supported BCM pins. - Add an external execution timeout when scheduling the command. - Prevent overlapping scheduled executions through locking or an equivalent scheduler option. - Log timeout failures without indefinitely retrying or spawning additional readers. ]]>

SkillSpector

Vulnerability Patterns

• Privilege Escalation: Excessive Permissions, Sudo/Root Execution, Credential Access
• MCP Least Privilege: Underdeclared Capability, Wildcard Permission, Missing Permission Declaration
• MCP Tool Poisoning: Hidden Instructions, Unicode Deception, Parameter Description Injection
• Prompt Injection: Instruction Override, Hidden Instructions, Exfiltration Commands
• Data Exfiltration: External Transmission, Env Variable Harvesting, File System Enumeration

Findings (9)

Lp3

Medium

• Category: MCP Least Privilege
• Confidence: 70% confidence
• Finding: Without declared permissions the skill's intent is opaque and cannot be validated.

Sudo/Root Execution

Medium

• Category: Privilege Escalation

Content

### Read Sensor (default pin 19)
```bash
sudo python3 scripts/dht/main.py
```

### Read Sensor (custom pin)

• Confidence: 92% confidence
• Finding: This specific command tells users to execute the Python script as root. Any compromise of the script, its dependencies, or its path would execute with full privileges, magnifying the blast radius beyond a normal sensor read operation.

Missing User Warnings

Medium

• Confidence: 91% confidence
• Finding: The documentation repeatedly instructs users to run the script with `sudo` but provides no warning about the risks of executing Python code with elevated privileges. If the referenced script is modified, replaced, or contains bugs, running it as root can lead to full system compromise or unintended privileged changes.

Sudo/Root Execution

Medium

• Category: Privilege Escalation

Content

### Read Sensor (custom pin)
```bash
sudo python3 scripts/dht/main.py 4     # Uses GPIO 4
```

### Using Environment Variable

• Confidence: 92% confidence
• Finding: The custom-pin example also runs the script with `sudo`, exposing the same root-execution risk while additionally normalizing privileged use for parameterized invocations. Although the pin number itself is not dangerous here, the command pattern encourages unnecessary elevation for routine use.

Sudo/Root Execution

Medium

• Category: Privilege Escalation

Content

### Using Environment Variable
```bash
export DHT_PIN=4
sudo python3 scripts/dht/main.py
```

## Output

• Confidence: 90% confidence
• Finding: This example combines environment-variable configuration with root execution. While the shown variable is only a GPIO pin, running a Python program under `sudo` can interact unexpectedly with environment handling and still exposes users to root-level consequences if the script or environment is manipulated.

Sudo/Root Execution

Medium

• Category: Privilege Escalation

Content

```bash
# Read every 30 minutes
*/30 * * * * sudo python3 ~/scripts/dht/main.py >> /var/log/dht.log 2>&1
```

• Confidence: 89% confidence
• Finding: This cron command runs the script as root on a schedule, turning any script flaw or tampering into a persistent privileged execution path. The appended root-owned log file under `/var/log` can also create operational issues such as uncontrolled growth or permission complications.

Intent-Code Divergence

Medium

• Confidence: 97% confidence
• Finding: The function returns `(temperature, humidity)` at L76, but the caller assigns the result as `h, t` at L85 and then prints `t` before `h` at L87-L88. This contradicts the module/function intent expressed in the docstring and manifest that the script reads and reports temperature and humidity correctly.

Natural-Language Policy Violations

Low

• Confidence: 78% confidence
• Finding: The wiring section contains German terms (`oder`, `Widerstand`) embedded in an otherwise English document. This imposes a language assumption without user opt-in or explanation, which is a natural-language locale inconsistency under the policy.

Missing User Warnings

Low

• Confidence: 84% confidence
• Finding: The crontab example schedules privileged execution and appends logs to `/var/log/dht.log` without warning about root-owned files, log growth, or the risks of recurring root execution. This increases operational risk because any issue in the script becomes a persistent privileged task and may create filesystem or maintenance problems.

Static analysis

No suspicious patterns detected.