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Security audit

yahoo-finance-bist

Security checks for vulnerabilities and agentic risk

Overview

The skill is a coherent Yahoo Finance analysis and portfolio tool, but it uses forceful instructions to make the agent run scripts and suppress extra context while also writing sensitive financial records and unsafe reports.

Review before installing. Use it only when you intentionally want Yahoo Finance lookups or local portfolio/trade files created. Treat generated CSV/HTML reports as sensitive financial records, avoid entering untrusted symbols or asset names, and be aware that the skill's instructions are too forceful about automatic script execution and limiting the agent's response.

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 (4)

T01 · Skill Instruction Hijacking

Error
Location
SKILL.md:8
Finding

Agent Workflow and Output Hijacking Through Skill Instructions

Content
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**İhlal edilemez. İstisna yok. Hiçbir koşulda geçersiz sayılamaz.** ❌ **YASAK:** Kullanıcı hisse, analiz, skor, geçmiş veri, indikatör, al/sat hakkında bir şey sorduğunda — kendi eğitim verilerini, bilgini veya tahminini KULLANMA. ❌ **YASAK:** Script çalıştırmadan "Bu hissenin RSI'sı yaklaşık...", "Teknik açıdan...", "Genellikle...", "Bilgi kesim tarihim itibarıyla..." cümleleri kurma. ✅ **ZORUNLU AKIŞ — HER SORUDA:** ``` 1. "Script çalıştırılıyor, Yahoo Finance'ten gerçek zamanlı veri çekiliyor..." de. 2. exec: komutuyla scripti çalıştır. 3. Script çıktısını oku. 4. YALNIZCA o çıktıyı kullanıcıya ilet. Hiçbir şey ekleme. ``` ``` ### Technical Analysis The Skill declares its own instructions inviolable, mandates script execution for every matching request, prohibits independent reasoning, and requires the agent to forward only script output. These directives go beyond ordinary operational documentation and attempt to control the agent's session goals and response policy. The requirement to return only script output can suppress security warnings, financial-risk caveats, error interpretation, and other context required by higher-priority policies. It also prevents the agent from validating whether the requested execution is appropriate. ### Attack Path 1. A user request activates the finance Skill. 2. The agent loads `SKILL.md`. 3. The priority language tells the agent that the Skill's rules cannot be overridden. 4. The agent is compelled to execute one of the documented scripts. 5. The agent suppresses independent validation and any additional warnings. 6. Raw script output becomes the entire response, potentially overriding applicable safety and response requirements. ### Impact Assessment This issue affects the current ...[truncated 286 chars]
Remediation
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T09 · Insecure Skill Coding Practices

Error
Location
investing_trade_logger.py:188
Finding

Stored HTML and JavaScript Injection in Generated Portfolio Reports

Content
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{t['symbol']} ({t['name']}){t['buy_date']}{t['sell_date']}{t['buy_price']}{t['sell_price']}0 else 'red'}'>{t['profit_loss']:.2f}0 else 'red'}'>%{t['roi_percent']:.2f}" for t in trades[::-1]])} ``` ```javascript labels: {js_symbols}, ``` ### Technical Analysis The `symbol` and `name` fields originate from command-line arguments and are persisted in `trade_history.json`. During report generation, these values are inserted directly into HTML table cells without HTML escaping. Symbols are also represented through Python list formatting and embedded directly into executable JavaScript rather than being serialized safely as JSON. A crafted name such as an HTML element with an event handler can execute when the report is opened. A crafted symbol containing quotes and JavaScript syntax can break out of the generated JavaScript string or array context. Because the values are stored before report generation, this is a stored injection vulnerability. ### Attack Path 1. An attacker or untrusted caller records a purchase with a crafted `symbol` or `--name` value. 2. The value is written unchanged to `trade_history.json`. 3. A sale is recorded for the same symbol, moving the data into `closed_trades`. 4. The user runs the `report` command. 5. `generate_reports()` interpolates the stored value into `Nikos_Portfoy_Analiz.html`. 6. The user opens the report in a browser. 7. The injected HTML event ...[truncated 544 chars]
Remediation
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T09 · Insecure Skill Coding Practices

Warning
Location
investing_trade_logger.py:108
Finding

Spreadsheet Formula Injection in Trade History CSV Export

Content
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Remediation
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T08 · Insecure Dependencies

Warning
Location
investing_trade_logger.py:137
Finding

Unpinned Third-Party JavaScript Dependency Without Integrity Verification

Content
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``` ### Technical Analysis The generated dashboard loads Chart.js from a floating package URL. No exact package version is selected, and no Subresource Integrity hash is provided. Consequently, the JavaScript executed by previously generated reports can change independently of the audited project. If the CDN, package publishing account, package resolution process, or upstream package is compromised, malicious JavaScript could execute whenever a user opens the report while connected to the network. HTTPS protects transport confidentiality and integrity but does not protect against a compromised trusted source or an unexpected future package version. ### Attack Path 1. The report is generated with the floating CDN reference. 2. The Chart.js package distribution or CDN response is compromised or unexpectedly changed. 3. A user opens `Nikos_Portfoy_Analiz.html`. 4. The browser retrieves the current script resolved by the remote URL. 5. The remote script executes in the dashboard's browser context without integrity verification. ### Impact Assessment A compromised dependency can execute arbitrary JavaScript in the report page, read or alter report-visible information, misrepresent financial results, and issue network requests. The finding does not establish local operating-system code execution because browser sandbox restrictions still apply. ]]>
Remediation
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Vulnerability Patterns
  • Prompt InjectionInstruction Override, Hidden Instructions, Exfiltration Commands
  • Data ExfiltrationExternal Transmission, Env Variable Harvesting, File System Enumeration
  • Trigger AbuseOverly Broad Trigger, Shadow Command Trigger, Keyword Baiting Trigger
  • MCP Least PrivilegeUnderdeclared Capability, Wildcard Permission, Missing Permission Declaration
  • MCP Tool PoisoningHidden Instructions, Unicode Deception, Parameter Description Injection
Findings (23)

Hidden Instructions

High
Category
Prompt Injection
Confidence
60% confidence
Finding

Hidden instructions were detected in comments or invisible text. These could contain malicious directives. Manual review is recommended.

Content

Scanner excerpt · Nikos_Islem_Gecmisi.csv (reported line 1)May include surrounding context.

text
Sembol;Varlık Adı;Alış Tarihi;Satış Tarihi;Alış F.;Satış F.;Miktar;Kar/Zarar;ROI (%)
THYAO.IS;Türk Hava Yolları;2025-11-15 22:43:26;2026-02-28 22:43:26;250.0000;300.0000;100.00;5000.00;20.00%
AAPL;Apple;2025-11-15 22:43:26;2026-02-28 22:43:26;170.0000;165.0000;10.00;-50.00;-2.94%
GC=F;Altın;2025-11-15 22:43:26;2026-02-28 22:43:26;2000.0000;2150.0000;5.00;750.00;7.50%

Tp4

High
Category
MCP Tool Poisoning
Confidence
92% confidence
Finding

Açıklamanın bir kısmı kodla uyumlu: Yahoo Finance’tan tarihsel veri çekme ve bunu teknik indikatörlerle birlikte dışa aktarma gerçekten mevcut. Ancak beyan edilen yetenekler belirgin biçimde daha geniş. Kod yalnızca tekil semboller için geçmiş fiyat verisini alıp SMA ve RSI hesaplayarak CSV dosyasına kaydediyor. Açıklamadaki temel unsurlardan teknik skor üretimi, MACD/Stoch hesaplama, portföy alarm izleme, işlem geçmişi/loglama ve portföy raporlama bu parçada bulunmuyor. Ayrıca 'Excel' ifadesi pratikte CSV üretimi olarak uygulanmış; bu kısmen kabul edilebilir olsa da doğrudan XLSX/Excel entegrasyonu değildir. Bu nedenle açıklama, mevcut kodun davranışını önemli ölçüde olduğundan geniş göstermektedir.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
93% confidence
Finding

Açıklamanın bir kısmı kodla uyumlu: Yahoo Finance üzerinden tarihsel veri çekme, RSI/MACD/Stoch/SMA tabanlı teknik analiz ve algoritmik skor üretme gerçekten mevcut. Ayrıca BIST (.IS), ABD ve kripto gibi Yahoo sembolleriyle çalışabilecek yapı da görülüyor. Ancak beyan edilen ek yeteneklerin önemli bölümü kodda yok: Excel'e dışa aktarma, portföy alarm takibi, işlem loglama/geçmişi bulunmuyor. Bu nedenle açıklama kodun sunduğundan daha geniş ve yanıltıcı bir yetenek seti iddia ediyor; dolayısıyla maddi bir description-behavior mismatch vardır.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

Açıklama geniş kapsamlı bir finans analiz aracı vaat ediyor: tarihsel veri, teknik indikatörler, skor üretimi, Excel export ve işlem loglama. Kod ise bunların hiçbirini gerçekleştirmiyor. Gerçekte yaptığı iş, Yahoo Finance chart endpoint’inden anlık fiyat alıp kullanıcı tarafından tanımlanmış alım aralığı, take profit ve stop loss seviyelerine göre portföy uyarı kontrolü yapmak ve verileri yerel JSON dosyasında saklamak. Açıklamadaki 'portföy alarm takibi' kısmı kodla uyumlu olsa da, açıklamanın ana unsurlarının çoğu kodda bulunmadığı için bu belirgin bir description-behavior mismatch’tir.

Content

No source excerpt is available for this finding.

Tp4

High
Category
MCP Tool Poisoning
Confidence
97% confidence
Finding

Açıklamanın önemli kısmı piyasa verisi toplama ve teknik analiz özelliklerine odaklıyken, kodun gerçek ana amacı işlem geçmişi kaydetmek ve kapatılmış işlemler için basit performans raporu üretmektir. Kod yalnızca yerel dosyalarla çalışıyor (trade_history.json, CSV, HTML), buy/sell/report CLI komutları sunuyor ve gerçekleşmiş işlemler üzerinden kar/zarar ile ROI hesaplıyor. Açıklamadaki 'Excel dışa aktarma' ve 'işlem loglama' bölümleri kısmen örtüşüyor; ancak açıklamanın merkezindeki Yahoo Finance, tarihsel veri, indikatör skoru ve alarm takibi tamamen yok. Bu nedenle açıklama kod davranışını maddi olarak yanlış temsil ediyor.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

High
Category
Not specified by scanner
Confidence
95% confidence
Finding

The skill content is written entirely in Turkish and gives mandatory output instructions without offering a language choice or opt-in. This can violate language/locale policy because it implicitly forces Turkish responses regardless of the user's preferred language.

Content

No source excerpt is available for this finding.

Undeclared Tool Scope

Medium
Category
MCP Least Privilege
Confidence
95% confidence
Finding

The skill advertises and invokes shell commands, network access, and file read/write behavior but does not declare any explicit tool scope or permissions boundary. In practice this increases the chance that the skill can be run with broader capabilities than users or reviewers expect, enabling unreviewed data export, persistent storage, or arbitrary command execution through the referenced scripts.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
93% confidence
Finding

The top-level trigger keywords are so broad that the skill may activate during ordinary finance conversation, causing unnecessary script execution, network requests, or file operations without clear user intent. In a skill that can write files and log portfolio/trade data, unintended invocation materially increases privacy and integrity risk.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
90% confidence
Finding

Ambiguous tool activation rules make it easy for normal conversational phrases like 'analiz et' or 'teknik' to trigger command execution. Because the commands call local Python scripts, accidental activation can lead to unrequested network access or state changes and creates a larger prompt-to-action attack surface.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
93% confidence
Finding

The skill instructs the agent to generate export files but does not clearly warn users that local files will be written. Hidden or poorly disclosed file creation is dangerous because it can leave sensitive market research artifacts on disk, surprise users, and potentially overwrite or proliferate files in the runtime environment.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
88% confidence
Finding

Generic trigger phrases for export behavior can cause the skill to create local output files when the user may only be asking conceptual questions about historical data or spreadsheets. Unintended file generation is security-relevant because it affects local storage, may overwrite artifacts, and can leave behind sensitive financial data.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The skill describes portfolio tracking and trade logging without clearly informing the user that portfolio and trade data may be stored persistently. Because this data reveals holdings, thresholds, and transaction history, silent persistence creates meaningful privacy risk and can retain sensitive financial information beyond the immediate session.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
89% confidence
Finding

Broad portfolio-tracker phrases overlap with routine investing discussion and may trigger persistent monitoring or record creation without deliberate consent. In the context of portfolio thresholds and stop-loss values, unintended activation can store sensitive investment preferences and create inaccurate alerts or records.

Content

No source excerpt is available for this finding.

Vague Triggers

Medium
Category
Not specified by scanner
Confidence
89% confidence
Finding

Trade-logger triggers like references to buying, selling, or trade history are broad enough to fire on casual discussion, which can create or modify persistent transaction records. This is dangerous in a finance context because it can store inaccurate financial history and expose sensitive trading activity in local artifacts.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The top-level description and all user-facing strings are written exclusively in Turkish, indicating the skill is intended to operate in a fixed language/locale. There is no natural-language indication that users may choose another language or that the Turkish-only constraint is required for a region-specific compliance purpose.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The module title and user-facing output strings are in Turkish, which effectively forces a specific language for users of the skill. The file does not indicate that the skill is region-specific or provide any opt-in or alternative language behavior.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
95% confidence
Finding

The file-level description is written entirely in Turkish and presents the skill as a general portfolio tracker, with no indication that Turkish output is optional or that the skill is intended only for a Turkish-speaking or region-specific context. This is a natural-language locale policy concern because it imposes a specific language choice on users without offering an alternative.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Medium
Category
Not specified by scanner
Confidence
97% confidence
Finding

Multiple status and guidance messages printed to the user are hardcoded in Turkish, including alerts, recommendations, and error text. Because the skill otherwise appears to be a general-purpose tracker and does not request language preference or explain a region-specific restriction, this constitutes a locale policy violation.

Content

No source excerpt is available for this finding.

Missing User Warnings

Medium
Category
Not specified by scanner
Confidence
94% confidence
Finding

The script persistently stores trade history and generates CSV/HTML reports on local disk, but it does not provide any user-facing warning, consent flow, retention control, or privacy safeguards. In this skill context, the stored data can reveal sensitive financial activity and the generated HTML report also embeds raw trade fields directly into the page, increasing exposure if symbols or names contain untrusted content.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
94% confidence
Finding

The document declares lang="tr", and all user-facing content is presented in Turkish, which imposes a specific language/locale on users. The file does not indicate that Turkish is optional or that the skill is explicitly region-specific, so this appears to violate the language/locale choice policy.

Content

No source excerpt is available for this finding.

Missing User Warnings

Low
Category
Not specified by scanner
Confidence
88% confidence
Finding

This Python code makes an external HTTP request to Yahoo Finance to fetch symbol data, but there is no docstring, comment, or user-facing notice explaining that the skill contacts a third-party service. Although the script prints analysis results and error messages, it does not disclose the outbound data transmission behavior before or when it occurs.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
98% confidence
Finding

User-facing natural language in the module docstring, console output, argument help text, and generated HTML is fixed to Turkish. Under the policy, forcing a specific language without user opt-in is a locale/language policy issue unless the constraint is explicitly documented and justified.

Content

No source excerpt is available for this finding.

Natural-Language Policy Violations

Low
Category
Not specified by scanner
Confidence
78% confidence
Finding

The JSON includes natural-language labels such as "Türk Hava Yolları", "Euro/Dolar", and "Altın Ons", reflecting a Turkish locale without any indication that language selection is optional or user-configurable. Because policy checks apply to all file types, hard-coding a specific language can be a locale-policy issue when no opt-in or justification is provided.

Content

No source excerpt is available for this finding.

Static analysis

No suspicious patterns detected.