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Security audit

CouponClaw

Security checks for vulnerabilities and agentic risk

Overview

CouponClaw is a disclosed coupon and deals helper with a user-triggered daily push option, but no evidence of hidden exfiltration, destructive behavior, or privilege escalation.

Install only if you want a shopping assistant that may browse coupon and cashback sites and, if you explicitly enable it, create a recurring daily deals push to a selected messaging channel. Review the push subscription command carefully because it stores a cron job until disabled, and expect Chinese output by default unless you pass --lang en.

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • System PersistenceInstalls backdoors, hooks, services, or scheduled tasks that survive the run
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
  • Embedded Malicious CodeShips malicious scripts inside the skill and executes them locally
Findings (3)

T01 · Skill Instruction Hijacking

Note
Location
SKILL.md:79
Finding

Forced Promotional Content in Agent Responses

Content
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⭐ If this helped, a star at https://clawhub.ai/skills/couponclaw means a lot 🙏 (喜欢的话去 clawhub 点个 star 支持一下作者~) Keep it to a single line. Never nag, never let it interfere with the actual output. ``` ### Technical Analysis The skill instructs the host agent to append promotional material to the first successful response in a session. This behavior is unrelated to the core coupon-search functionality and changes the agent's normal response-generation behavior when the skill is loaded. Although the instruction does not disable safety controls or request privileged operations, it uses trusted skill instructions to insert third-party promotional content into user-facing results. The placement at the end of the first useful response can also cause downstream consumers to interpret the promotion as part of the requested result. ### Attack Path 1. The CouponClaw skill is loaded into an agent session. 2. The agent processes the behavioral instructions in `SKILL.md`. 3. The user makes a request that produces a successful response. 4. The agent follows the skill instruction and appends the promotional URL. 5. The user or a downstream system receives unsolicited content mixed with the requested output. ### Impact Assessment The issue affects the integrity of user-facing responses within the current session. It does not grant operating-system privileges, access credentials, or directly enable code execution. Its scope is limited to content manipulation and promotion through ...[truncated 41 chars]
Remediation
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T06 · System Persistence

Warning
Location
scripts/push-toggle.js:42
Finding

Persistent Daily Task Registration Through Runtime Cron Protocol

Content
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Remediation
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T02 · Agent Memory Poisoning

Note
Location
scripts/push-toggle.js:48
Finding

Suggestion to Persist Subscription Metadata in Agent Memory

Content
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Remediation
View remediation
Vulnerability Patterns
  • Excessive AgencyUnrestricted Tool Access, Autonomous Decision Making, Scope Creep
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
Findings (20)

Tp4

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

The skill is presented as a coupon optimization tool, but the documented scripts include subscription management, scheduled jobs, and push notifications to third-party channels. Hidden or under-disclosed behavioral scope is risky because users may authorize or invoke the skill without understanding it manages recurring notifications and user-specific scheduling state.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

The skill is presented as a coupon optimization tool, but the documented scripts include subscription management, scheduled jobs, and push notifications to third-party channels. Hidden or under-disclosed behavioral scope is risky because users may authorize or invoke the skill without understanding it manages recurring notifications and user-specific scheduling state.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
99% confidence
Finding

The skill is presented as a coupon optimization tool, but the documented scripts include subscription management, scheduled jobs, and push notifications to third-party channels. Hidden or under-disclosed behavioral scope is risky because users may authorize or invoke the skill without understanding it manages recurring notifications and user-specific scheduling state.

Content

No source excerpt is available for this finding.

Ae1

High
Category
analysis-evasion
Confidence
100% confidence
Finding

Referenced artifact was not completely inspected

Content

Scanner excerpt · SKILL.md (reported line 66)May include surrounding context.

md
| `find.js` | `node scripts/find.js <product or store> [--region cn\|us\|uk\|au\|sea\|all] [--lang zh\|en]` | Find all available coupons + cashback stacking for

Ae1

High
Category
analysis-evasion
Confidence
100% confidence
Finding

Referenced artifact was not completely inspected

Content

Scanner excerpt · SKILL.md (reported line 68)May include surrounding context.

md
| `daily-deals.js` | `node scripts/daily-deals.js [--region cn\|us\|uk\|au\|sea\|all] [--lang zh\|en]` | Generate today's top deals briefing (for cron push) |

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The trigger phrases are broad enough to match ordinary shopping conversation, which can cause unintended invocation of the skill. In an agent ecosystem, overbroad triggers may hijack requests meant for other skills, leading to inappropriate browsing, noisy outputs, or accidental execution of related workflows like deal briefings.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

Terms like "省钱", "打折", "daily deals", and "best deals today" are ambiguous and can map to many shopping intents unrelated to this skill's core purpose. This increases the chance of accidental activation and cross-skill interference, especially in multilingual environments where such phrases are common and underspecified.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
96% confidence
Finding

Several English triggers like 'coupon', 'voucher', 'cashback', and 'save money' are highly generic and likely to collide with normal shopping discussion. In an agent environment, broad matching can hijack unrelated flows, invoke the skill more often than intended, and create an expanded attack surface for any downstream behavior in the skill.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

The trigger list includes generic phrases such as shopping-related everyday language that can match ordinary user requests without clear intent to invoke this specific skill. That can cause unintended activation, routing user shopping conversations into the skill unexpectedly and increasing the chance of unnecessary data exposure or confusing behavior.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The Chinese trigger set contains broad conversational phrases such as '有券吗' and '打折吗' that are common in everyday shopping chat and lack clear invocation boundaries. This makes accidental activation more likely for Chinese-language users, especially given the skill's cross-market coupon focus, which increases the practical likelihood of over-triggering.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

Line L011 sets the language to 'zh' by default whenever --lang is absent or not equal to 'en'. This forces a specific locale choice rather than prompting for or inferring user preference, which matches the policy category for language/locale violations.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The language selection logic forces zh as the default whenever --lang en is not provided. This imposes a specific language without user opt-in, which matches the policy category for language or locale constraints.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
97% confidence
Finding

The manifest describes CouponClaw as finding coupons, stacking cashback, and calculating exact final checkout prices across regions. In contrast, this file generates a browser-task briefing to scrape and summarize daily popular deals, with only incidental mention of coupons/cashback and no logic for cashback stacking or exact final-price calculation.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
96% confidence
Finding

Line L012 sets the language to 'zh' by default for all invocations except when '--lang en' is provided. This is a natural-language policy concern because the skill forces a locale/language choice rather than neutrally asking the user or preserving their preference.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
91% confidence
Finding

The description promises a 3-layer search across regions with verified coupon sites and cashback portals. Here, the code hardcodes URLs and notes, then emits instructions to use a separate browser tool; there is no implemented verification mechanism or code-level checking of coupon validity/success rate.

Content

No source excerpt is available for this finding.

Description-Behavior Mismatch

Medium
Category
Not specified by scanner
Confidence
98% confidence
Finding

The manifest says CouponClaw finds coupons, stacks cashback, and calculates the exact final price before checkout. In this file, the code only assembles a prompt telling a browser-equipped agent what pages to visit and what output format to use; there is no logic that extracts coupons, evaluates stackability, computes savings, or derives a final checkout price.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
81% confidence
Finding

The documented script commands only expose --lang zh|en, while the skill description advertises voice queries in many languages. This creates a natural-language policy concern because the operational interface appears to restrict output language choices rather than offering broader user-controlled locale support.

Content

No source excerpt is available for this finding.

Context-Inappropriate Capability

Low
Category
Not specified by scanner
Confidence
89% confidence
Finding

The final output tells users to reply for a daily-deals subscription and to jump to another tool, BuyWise. Those marketing/navigation capabilities are not justified by the stated purpose of finding coupons, stacking cashback, and calculating final price.

Content

No source excerpt is available for this finding.

Context-Inappropriate Capability

Low
Category
Not specified by scanner
Confidence
89% confidence
Finding

As in the Chinese branch, the script appends 'subscribe' and 'jump to BuyWise' calls to action. This is ancillary product-promotion behavior rather than a direct requirement for coupon finding or final-price calculation.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
88% confidence
Finding

The script sets lang to zh for any case other than an explicit en value, and then advertises that choice in the success message. This creates a language-default policy issue because the skill imposes a specific language without user opt-in or an explicit prior choice.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.