Pywayne Crypto

• Outcome: Review
• Latest audit: Sep 10, 2026 · 7:33 PM UTC
• Version: 0.1.0

Overview

This skill is coherent, but it gives users weak encryption patterns for sensitive data, including a default key and XOR fallback.

Review before installing or using for real secrets. Do not rely on the default key or XOR fallback for passwords, tokens, database credentials, or confidential data; require strong user-provided keys and authenticated encryption from a verified implementation.

A.I.G

Vulnerability Patterns

• 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
• Remote Payload Retrieval and Execution: Fetches external code whose behavior can change after review
• Embedded Malicious Code: Ships malicious scripts inside the skill and executes them locally

Findings (1)

T09 · Insecure Skill Coding Practices

Warning

• Location: SKILL.md:115

Finding

Weak XOR Fallback and Unspecified Default Encryption Key

Content

View full analysis

Vulnerability Details

File Location: SKILL.md:30-31 and SKILL.md:115-121
Vulnerability Type: Insecure cryptographic design guidance
Risk Level: Medium

Vulnerable Documentation Excerpts

English rendering of SKILL.md:30-31:

text

password | str | Optional custom password. If omitted, a default key is used.

English rendering of SKILL.md:115-121:

markdown

## Encryption Strategy

The module uses a layered encryption strategy, preferring Fernet and falling back to XOR.

| Strategy | Description |
|----------|-------------|
| **Fernet encryption** (recommended) | AES-128 symmetric encryption with message-integrity verification |
| **XOR encryption** (fallback) | Simple XOR encryption with no dependencies, providing basic functionality |
| **Code obfuscation protection** | Base64 concealment, dynamic function generation, and namespace cleanup |

Technical Analysis

The Skill documentation promotes encryption of potentially sensitive strings and configuration credentials while allowing two unsafe modes:

1. Encryption may use an unspecified default key when the caller does not provide a password. If this key is static or shared between installations, obtaining it from one copy of the external library could permit decryption of data produced by other users.
2. The cryptographic process may automatically fall back to XOR. Basic XOR encryption does not provide modern confidentiality or integrity guarantees and is vulnerable to known-plaintext analysis, key-reuse attacks, frequency analysis, and ciphertext modification.

Automatic fallback from authenticated encryption to a materially weaker algorithm is a fail-open design. Callers may believe that protected data always receives Fernet-equivalent confidentiality and authentication even when the weaker path is active.

The project contains only SKILL.md; no implementation is included. Consequently, the precise default key, XOR c ...[truncated 2099 chars]

Remediation

View remediation

Remediation Suggestions

1. Remove the XOR fallback entirely and fail closed if the authenticated-encryption dependency is unavailable.
2. Remove the implicit default-key mode. Require callers to provide securely generated key material or retrieve it from an approved secret-management system.
3. Use authenticated encryption exclusively, such as Fernet or a carefully implemented AEAD construction.
4. If passwords must be accepted, derive encryption keys with a password-based key derivation function such as Argon2id, scrypt, or PBKDF2 using a unique random salt and an appropriate work factor.
5. Generate unique nonces or initialization vectors according to the selected algorithm and never reuse them where reuse is unsafe.
6. Store algorithm and key-derivation metadata in a versioned ciphertext envelope so decryption does not silently downgrade to a weaker scheme.
7. Return a clear error when secure encryption cannot be performed. Never substitute encoding or obfuscation for encryption.
8. Document key rotation, secret storage, integrity guarantees, and failure behavior.
9. Add tests confirming that missing dependencies, omitted keys, malformed ciphertext, and authentication failures cannot trigger XOR or another weak fallback.
10. Clarify that Base64 encoding and code obfuscation provide no cryptographic confidentiality.

SkillSpector

Vulnerability Patterns

• Prompt Injection: Instruction Override, Hidden Instructions, Exfiltration Commands
• Data Exfiltration: External Transmission, Env Variable Harvesting, File System Enumeration
• Privilege Escalation: Excessive Permissions, Sudo/Root Execution, Credential Access
• Supply Chain: Unpinned Dependencies, External Script Fetching, Obfuscated Code
• Excessive Agency: Unrestricted Tool Access, Autonomous Decision Making, Scope Creep

Findings (1)

Natural-Language Policy Violations

Medium

• Category: Not specified by scanner
• Confidence: 94% confidence

Finding

This markdown skill documentation presents the operational instructions and examples in Chinese, which effectively forces a specific language for users who invoke or rely on the skill. The policy allows locale constraints only when user choice is offered or when the restriction is explicitly justified, neither of which is present here.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.