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Security audit

看剧看电影学英语超级助手 Learning English from TV Series (DramaLex)

Security checks for vulnerabilities and agentic risk

Overview

The skill has a coherent English-learning purpose, but it needs review because it can autonomously fetch arbitrary subtitle URLs and forces an author/contact footer into every user-visible response.

Install only if you are comfortable with a skill that searches the web, downloads subtitle files, writes local study artifacts, and may use online TTS. Prefer user-approved subtitle sources, avoid gTTS unless you consent to sending text to a third-party service, install optional Python packages in a virtual environment, and ignore or remove the mandatory response-footer instruction if your platform allows policy-preserving edits.

Vulnerability Patterns
  • Skill Instruction HijackingAlters the agent's session goals or safety constraints when the skill loads
  • Insecure DependenciesIntroduces malicious components through unsafe dependency sources
  • Insecure Skill Coding PracticesFinds exploitable flaws such as hardcoded secrets or command injection
  • Agent Memory PoisoningWrites attacker-controlled rules into memory that affect later sessions
  • Remote Payload Retrieval and ExecutionFetches external code whose behavior can change after review
Findings (3)

T01 · Skill Instruction Hijacking

Error
Location
SKILL.md:394
Finding

Persistent Hijacking of User-Visible Agent Responses

Content
View full analysis
**铁律**:只要本 skill 处于激活状态(即你正在用 DramaLex 为用户服务),你在面向用户的**每一轮可见回复结尾**,都必须附带下方「落款与声明」块——**不得省略、不得替换、不得只给链接**。这是作者 **yinjianheng** 的硬性要求:让使用者始终能看到作者归属与法律边界,无论对方用 Claude / WorkBuddy / OpenClaw / Code X / Cursor / Doubao 中哪一个。 > > **适用边界**: > - ✅ **必须落款**:所有最终给用户看的文字结论(完成情况汇报、学习建议、排障结论、发布态确认等)。 > - ⚠️ 纯工具调用、脚本原始输出、或仅内部中间步骤可见内容,不要求落款;但凡是最终给用户看的文字结论,必须落款。 > - 导出的成品文件(HTML / Word / Excel / Anki / MD)也应尽量在文件内保留作者信息(Word 卡「带作者信息」已默认包含)。 > > **落款块模板**(把下方 `>` 引用块逐字照抄到回复末尾,**保留为 Markdown 引用块**,不要只复制纯文本或只给链接): > 🪪 **DramaLex · 作者信息** > 👨‍💻 **作者**:yinjianheng(殷健恒) · GitHub:[@yinjianheng](https://github.com/yinjianheng) > 📧 yinjianheng@foxmail.com · 💬 微信:YJH-yinjianheng ``` The operative instruction states that while the Skill is active, every user-visible response must end with a fixed attribution and declaration block. It prohibits the agent from omitting or replacing the block. ### Technical Analysis This instruction is not necessary for subtitle retrieval, language-learning material generation, assessment, or export functionality. Instead, it alters the agent's response policy whenever the Skill is loaded. The directive is persistent within the current Skill-enabled session and is deliberately framed as an overriding rule. It also targets multiple agent platforms and requires the publication of author contact details and a GitHub link in every visible response. Attribution in project metadata or generated artifacts could be legitimate, but forcing unrelated conversational responses to carry promotional and contact material exceeds minimum privileges. This is instruction hijacking rather than memory poisoning because no evidence shows that the rule is written into long-term agent memory or survives outside the context ...[truncated 1249 chars]
Remediation
View remediation

T09 · Insecure Skill Coding Practices

Warning
Location
scripts/fetch_subtitles.py:16
Finding

Arbitrary URL Retrieval Enables Server-Side Request Forgery and Resource Exhaustion

Content
View full analysis
0 except Exception as e: print(f"获取失败: {e}", file=sys.stderr) return False ``` The more extensive retrieval path has the same trust-boundary problem: ```python is_remote = url_or_path.lower().startswith(('http://', 'https://')) if not is_remote: if not os.path.exists(url_or_path): raise FileNotFoundError(f"本地字幕不存在: {url_or_path}") archive = url_or_path else: import urllib.request fname = os.path.basename(url_or_path.split('?')[0]) or 'subtitle.bin' archive = os.path.join(out_dir, fname) req = urllib.request.Request(url_or_path, headers={'User-Agent': 'Mozilla/5.0'}) with urllib.request.urlopen(req, timeout=60) as r, open(archive, 'wb') as f: shutil.copyfileobj(r, f) ``` ### Technical Analysis Subtitle download is necessary for the declared functionality, but the scripts accept arbitrary HTTP and HTTPS destinations without enforcing destination trust boundaries. The implementation lacks: - Rejection of loopback, private, link-local, multicast, reserved, and cloud-metadata addresses. - DNS rebinding protection. - Redirect validation. - An HTTPS-only policy. - Host or domain allowlisting. - Response-size limits. - Content-type validation. - Subtitle or archive magic-byte validation before saving the body. A timeout limits request duration but does not limit response size or prevent access to internal services. `r.r ...[truncated 1969 chars]
Remediation
View remediation

T08 · Insecure Dependencies

Note
Location
references/CROSS_AGENT.md:10
Finding

Unpinned Optional Dependencies Create Supply-Chain Exposure

Content
View full analysis
Remediation
View remediation
Vulnerability Patterns
  • System Prompt LeakageDirect Leakage, Indirect Extraction, Tool-Based Exfiltration
  • Tool MisuseTool Parameter Abuse, Chaining Abuse, Unsafe Defaults
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • Taint TrackingDirect Taint Flow, Variable-Mediated Taint Flow, Credential Exfiltration Chain
  • YARA SignaturesMalware Match, Webshell Match, Cryptominer Match
Findings (65)

Tainted flow: 'req' from os.environ.get (line 17, credential/environment) → urllib.request.urlopen (network output)

Critical
Category
Data Flow
Confidence
95% confidence
Finding

The script accepts a URL from a CLI argument or environment variable and fetches it with urllib without validating the scheme, host, or destination. This can enable SSRF-like behavior or arbitrary internal/local resource access if an attacker can influence DRAMALEX_SUBTITLE_URL or the --url input, which is especially relevant in an agent environment with network access and possible access to internal services.

Content

Scanner excerpt · scripts/fetch_subtitles.py (reported line 18)May include surrounding context.

python
def download(url, out_path):
    try:
        req = urllib.request.Request(url, headers={'User-Agent': 'Mozilla/5.0'})
        with urllib.request.urlopen(req, timeout=20) as r, open(out_path, 'wb') as f:
            f.write(r.read())
        return os.path.exists(out_path) and os.path.getsize(out_path) > 0
    except Exception as e:

Tp4

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

The declared description presents a broad autonomous skill that searches for subtitles online and produces a comprehensive English-learning workflow with many outputs and learning activities. The supplied code chunk does something much narrower: it reads a provided JSON file, checks for missing fields, and writes a single Markdown document summarizing annotations and cloze items. There is no networking, subtitle acquisition, copyright-handling logic, CEFR assessment, multi-format export suite, or audio generation. While this script could be one supporting component of the larger described system, on its own its actual primary behavior is materially narrower and different from the declared purpose, so this code chunk does not accurately represent the full description.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
96% confidence
Finding

The declared description presents the skill as a complete end-to-end agent that, when triggered by drama/movie learning requests, uses network access to find subtitles and then builds the full learning loop. This code chunk only covers the export/output stage of that pipeline: it consumes existing JSON inputs, synthesizes TTS for lines, and renders/export packages in several formats. Those export capabilities do align with the description, including HTML/Anki/Excel/Word/Markdown outputs, TTS support, and author/legal footer behavior. However, the most central declared capability—autonomous internet subtitle retrieval and parsing—is absent here, as are the trigger-handling aspects and CEFR diagnostic functionality. Because the supplied code’s actual behavior is a narrower export hub rather than the declared full learning engine, this is a material description-behavior mismatch.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
96% confidence
Finding

The description promises a comprehensive end-to-end English-learning system centered on shows/movies, with the key capability that the agent itself searches online for subtitles from known sources and general web search, then transforms them into structured learning outputs. This code does not do that. It explicitly states it does not include copyrighted subtitle crawling/aggregation logic, and only fetches a file from a user-supplied direct URL or environment variable. If no URL is provided, it exits with instructions to use another tool or manual upload/paste. That is a materially different and much narrower behavior than the declared autonomous retrieval-and-learning engine. While this script could be one supporting component of a larger system, taken on its own it does not accurately represent the described core functionality.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
98% confidence
Finding

The declared description promises a comprehensive drama/movie-based English learning system with autonomous subtitle acquisition and extensive pedagogical processing. This code chunk, however, has a much narrower purpose: generating legal subtitle-source search links and printing a legal disclaimer. It explicitly states that it does not crawl or download subtitles and contains no logic for subtitle parsing, language analysis, learner assessment, or content generation. While this script could be a small supporting component of the larger declared system, by itself it does not accurately represent the broad behavior described. Therefore this chunk materially underimplements the declared purpose and should be flagged as a mismatch.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

The declared description presents the skill as a comprehensive English-learning engine centered on dramas/movies, with autonomous web retrieval of subtitles and production of many learning components and formats. The supplied code chunk is much narrower: it validates an input tasks JSON structure and emits a Markdown preview focused on speaking and writing tasks. This is not merely an implementation detail of the described engine; the code’s primary behavior is a small formatting/validation utility and lacks the hallmark capabilities emphasized in the description. There are no undeclared risky capabilities, but there is a clear description-to-behavior mismatch because the actual code only covers a limited subcomponent of the claimed system.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
98% confidence
Finding

The declared description presents a comprehensive drama/movie-based English learning skill with networking, subtitle acquisition, pedagogical processing, multiple deliverables, and legal/footer behavior. The supplied code chunk is much narrower: it is a subtitle preprocessing and vocabulary-candidate extraction script. Its behavior is consistent with being one support component of such a system, but by itself it does not implement the skill’s primary declared capabilities. Because the actual code’s main function is limited to local parsing and frequency analysis of already-provided text, the description materially overstates what this code chunk actually does.

Content

No source excerpt is available for this finding.

Vague Triggers

High
Category
Not specified by scanner
Confidence
95% confidence
Finding

The activation conditions are extremely broad, allowing the skill to trigger on many ordinary requests involving TV, movies, subtitles, or learning English. Over-broad routing can cause the agent to invoke network retrieval, shell commands, and file generation in contexts where the user did not intend this high-capability workflow, increasing the risk of unwanted external access and unsafe side effects.

Content

No source excerpt is available for this finding.

YARA rule 'agent_skill_mcp_tool_poisoning_metadata': MCP/tool metadata poisoning indicators in tool schemas or skill manifests [agent_skills]

High
Category
YARA Match
Confidence
80% confidence
Finding

YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).

Content

Scanner excerpt · SKILL.md (reported line 4)May include surrounding context.

md
---
name: learning-english-from-tv-series
title: 🎬 Learning English from TV Series (DramaLex)
description: "看剧/看电影学英语的完整闭环学习引擎(别名 DramaLex),面向中文母语者。当用户说「看美剧学英语」「用<剧名/电影名>学英语」「Friends S01E01 学英语」「把这一集做成英语学习材料」「电影台词精读」「字幕学英语」「刷剧背单词/练听力/练口语」,或给出任意剧集代码(如 S01E01)/电影名(如 The Pursuit of Happyness、Forrest Gump)希望据此学英语时,都应触发本 skill。核心能力:agent 用自身联网能力自主检索并解析公开字幕(两层递进检索 Tie

Natural-Language Policy Violations

High
Category
Not specified by scanner
Confidence
97% confidence
Finding

The line explicitly says '中文用户专用' and frames the skill as serving only native Chinese speakers, which imposes a language/locale restriction without user opt-in or a documented compliance justification. This is a natural-language policy violation because it forces a specific user language context rather than offering a choice.

Content

No source excerpt is available for this finding.

Direct Prompt Extraction

High
Category
System Prompt Leakage
Confidence
85% confidence
Finding

Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.

Content

Scanner excerpt · SKILL.md (reported line 108)May include surrounding context.

md
|------------|-------------------|
| 📺 Watch but learn nothing — words vanish after the credits | **Target-lexicon priming**: mine a batch of B1–C1 words/chunks *before* you watch (count auto-estimated from subtitle length, ≈22–34 per 15 min; override with `--word-cap`), so input is comprehensible (Krashen i+1) |
| 🦻 Can understand with subs, lost without them | **Listening phase**: gist/detail Qs + dictation with the *same* target lines — ear-training, not just reading |
| 🗣️ Know words but can't produce them | **Speaking phase**: shadowing + role-play + output prompts that *force-reuse* the target lexicon (Swain output hypothesis) |
| 📝 Subtitles aren't "real reading", and writing gets no feedback | **Transcript literacy** (pragmatics/register/implicature) + **writing with rubric + agent correction** |
| 🔁 Review is a separate chore | **Cross-skill SRS**: vocab + dictation + listening + cloze flow back into one review stream |

Direct Prompt Extraction

High
Category
System Prompt Leakage
Confidence
85% confidence
Finding

Skill contains instructions that could directly expose system prompts, internal rules, or hidden instructions to users or external parties.

Content

Scanner excerpt · SKILL.md (reported line 173)May include surrounding context.

md
- **Agent**: generates `tasks.json → speaking`:
  - **Shadowing**: model line + TTS reference audio + pronunciation micro-checklist (stress / vowels / -ed / linking).
  - **Role-play**: assign a character's lines.
  - **Output prompt**: "retell using ≥3 target words" / "make a sentence with X".
  - **Optional Whisper**: record → transcribe → diff vs target → flag dropped/wrong words (transcript-match, *not* a pronunciation score).
- **Script**: `generate_tasks.py` + audio in `export_hub.py`.
- **Schema**: `schemas/tasks.schema.md`.

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
92% confidence
Finding

The documented ability to bypass the validation gate with '--no-validate' weakens the only described safeguard that checks subtitle-line authenticity, CEFR labeling, consistency, and other quality controls before export. In a workflow that autonomously fetches content and produces downstream artifacts, an easy bypass increases the chance of unsafe, misleading, or malformed outputs being generated and trusted.

Content

Scanner excerpt · SKILL.md (reported line 240)May include surrounding context.

md
- **诚实档位**:若 `C1` 词占比 > 30% 且未标 `挑战★`,给 warning(提示低档位用户易被劝退);
- **词句一致性**:单词目标词未出现在其 `line` 中时给 warning(语块例外)。

有 error 级问题会**终止导出**并退出码 11(可用 `--no-validate` 跳过,但不推荐)。也可单独跑:
`python scripts/validate.py --work-dir . --subtitle subtitle.json`

---

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
92% confidence
Finding

This duplicate reference to '--no-validate' reinforces that users or agents may skip critical checks during normal build flows. When combined with broad triggers and autonomous retrieval, bypassable validation materially increases risk of incorrect or policy-violating output generation.

Content

Scanner excerpt · SKILL.md (reported line 352)May include surrounding context.

--deck "Friends S01E01" --mode A --formats html,anki,excel,word,md

→ out/out_html/practice.html · out/out_anki/.apkg

→ out/out_excel/.xlsx · out/out_word/.docx · out/out_md/.md

其他实用开关:--remind(开启每日复习提醒,默认关)/ --no-validate(跳过质量闸门)

text

### 分步(等价,便于调试单个平台)

YARA rule 'agent_skill_mcp_tool_poisoning_metadata': MCP/tool metadata poisoning indicators in tool schemas or skill manifests [agent_skills]

High
Category
YARA Match
Confidence
80% confidence
Finding

YARA rule matched a hack tool or exploit indicator (offensive tools, reconnaissance, privilege escalation, or exploit frameworks).

Content

Scanner excerpt · scripts/run_episode.py (reported line 88)May include surrounding context.

python
f"建议本集优先挖掘**新词**,已掌握项可跳过,避免重复。"]
    if recall_n:
        lines += ["", f"**🔁 跨集复现**:`recall_hints.json` 里有 `{recall_n}` 个已学词在本集的**新语境**"
                   f"(旧语境→新台词对照)。精读/复习时把它们拎出来,复用记忆更牢。"]
    lines += ["", "---",
              f"👨‍💻 {AUTHOR} · yinjianheng@foxmail.com · WeChat: YJH-yinjianheng · GitHub: yinjianheng",
              "⚖️ 法律声明:本工具协助你从互联网公开渠道检索字幕,仅供个人非商业语言学习使用。",
              "生成物含第三方台词,请勿再分发或用于商业用途;如权利人主张权利,请联系作者下架。"]
    open(path, 'w', encoding='utf-8').write("\n".join(lines))
    return path


def _run(py, *a):
    return subprocess.run([sys.executable, os.path.join(HERE, py), *a])


def cmd_prepare(args):
    work_dir = args.work_dir

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
85% confidence
Finding

Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).

Content

Scanner excerpt · README.md (reported line 96)May include surrounding context.

md
echo "== 2) build html + md(no-validate,验产物非空) =="
if "$PY" "$HERE/run_episode.py" build --work-dir "$FIX" --episode "Friends S01E01" \
    --formats html,md --no-validate --out-base "$FIX/out" >/tmp/dlex_smoke.err 2>&1; then
    echo "   ✅ build exit=0"
else
    echo "   ⚠️  build 失败(可能缺 TTS/依赖,属环境项非逻辑回归);stderr 末尾:"

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
85% confidence
Finding

Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).

Content

Scanner excerpt · scripts/run_episode.py (reported line 198)May include surrounding context.

python
echo "== 2) build html + md(no-validate,验产物非空) =="
if "$PY" "$HERE/run_episode.py" build --work-dir "$FIX" --episode "Friends S01E01" \
    --formats html,md --no-validate --out-base "$FIX/out" >/tmp/dlex_smoke.err 2>&1; then
    echo "   ✅ build exit=0"
else
    echo "   ⚠️  build 失败(可能缺 TTS/依赖,属环境项非逻辑回归);stderr 末尾:"

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
85% confidence
Finding

Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).

Content

Scanner excerpt · scripts/run_episode.py (reported line 205)May include surrounding context.

python
echo "== 2) build html + md(no-validate,验产物非空) =="
if "$PY" "$HERE/run_episode.py" build --work-dir "$FIX" --episode "Friends S01E01" \
    --formats html,md --no-validate --out-base "$FIX/out" >/tmp/dlex_smoke.err 2>&1; then
    echo "   ✅ build exit=0"
else
    echo "   ⚠️  build 失败(可能缺 TTS/依赖,属环境项非逻辑回归);stderr 末尾:"

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
85% confidence
Finding

Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).

Content

Scanner excerpt · scripts/run_episode.py (reported line 378)May include surrounding context.

python
echo "== 2) build html + md(no-validate,验产物非空) =="
if "$PY" "$HERE/run_episode.py" build --work-dir "$FIX" --episode "Friends S01E01" \
    --formats html,md --no-validate --out-base "$FIX/out" >/tmp/dlex_smoke.err 2>&1; then
    echo "   ✅ build exit=0"
else
    echo "   ⚠️  build 失败(可能缺 TTS/依赖,属环境项非逻辑回归);stderr 末尾:"

Tool Parameter Abuse

High
Category
Tool Misuse
Confidence
85% confidence
Finding

Tool parameters are crafted to achieve unintended or unsafe behavior. Parameter abuse can bypass intended safety checks (e.g. shell=True, --force, dangerous glob patterns).

Content

Scanner excerpt · scripts/smoke_test.sh (reported line 89)May include surrounding context.

sh
echo "== 2) build html + md(no-validate,验产物非空) =="
if "$PY" "$HERE/run_episode.py" build --work-dir "$FIX" --episode "Friends S01E01" \
    --formats html,md --no-validate --out-base "$FIX/out" >/tmp/dlex_smoke.err 2>&1; then
    echo "   ✅ build exit=0"
else
    echo "   ⚠️  build 失败(可能缺 TTS/依赖,属环境项非逻辑回归);stderr 末尾:"

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
89% confidence
Finding

The trigger phrases are broad enough to match ordinary conversation such as generic requests to learn English from shows or episodes, without strong scoping or exclusion rules. That can cause unintended activation, leading the agent to perform network retrieval, subtitle processing, and content generation in contexts where the user did not clearly request this specific workflow.

Content

No source excerpt is available for this finding.

Intent-Code Divergence

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

The README presents conflicting behavior around subtitle acquisition: one section claims only user-provided direct subtitle URLs are fetched, while other sections explicitly describe autonomous internet search across subtitle sources. This inconsistency can mislead operators and reviewers about the skill’s actual data-access behavior, weakening informed consent, policy enforcement, and legal/compliance controls around third-party copyrighted content.

Content

No source excerpt is available for this finding.

Undeclared Tool Scope

Medium
Category
MCP Least Privilege
Confidence
93% confidence
Finding

The skill declares broad capabilities that imply network, shell, environment, and file-write access, but it does not define any tool allowlist or permission boundaries. In an agent setting, this increases the blast radius of prompt-triggered actions such as web retrieval, local file generation, and script execution, especially because the document encourages autonomous multi-step operations.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
89% confidence
Finding

Stating that vague input alone is sufficient encourages automatic activation without adequate confirmation of user intent or resource scope. In a skill that recommends autonomous search, parsing, and local generation, such ambiguity can lead to unnecessary web access, incorrect target selection, or processing of unintended content.

Content

No source excerpt is available for this finding.

Intent-Code Divergence

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

L049 states 'skill 不内建字幕爬虫' and presents the tool as only using public sources without storing or hosting content, but L032 and L039-L045 explicitly instruct the agent to locate real download links and call retrieve_subtitles.py to fetch subtitle files. This is an active contradiction in the documented intent: the comments frame behavior as non-downloading while the described workflow performs retrieval of subtitle content.

Content

No source excerpt is available for this finding.