Data Poisoning: How API Vulnerabilities Compromise LLM Data Integrity

Cybersecurity has traditionally focused on protecting data. Sensitive information is a valuable target for hackers who want to steal or exploit it. However, an insidious threat, known as data poisoning, is rapidly emerging in the age of artificial intelligence (AI) and use of LLMs.

This type of attack flips the script – instead of outright data theft, data poisoning corrupts the integrity of the data itself.

AI and machine learning (ML) models are profoundly dependent on the data used to train them. They learn patterns and behaviors by analyzing massive datasets. This reliance is precisely where the vulnerability lies. By subtly injecting misleading or malicious data into these training sets, attackers can manipulate the model’s learning process. 

The result is a compromised LLM that, while outwardly functional, generates unreliable, or even actively harmful, results.

What is Data Poisoning?

Data poisoning is the intentional act of injecting corrupted, misleading, or malicious data into a machine learning model’s training dataset, in some cases by exploiting vulnerabilities in APIs, to skew its learning process. It’s a powerful tactic because even minor alterations to a dataset can lead to significant changes in the way a model makes decisions and predictions.

By subtly altering the statistical patterns within the training data, attackers essentially change the LLM’s internal model of how language or code should work, leading to inaccurate or biased results.

Here is a recent real-world example:

A recent security lapse on AI development platforms Hugging Face and GitHub exposed hundreds of API tokens, many with write permissions. This incident, reported by ISMG, highlights the very real threat of data poisoning attacks. With write access, attackers could manipulate the training datasets of major AI models like Meta’s Llama2 or Google’s Bloom – potentially corrupting their reliability and introducing vulnerabilities or biases.

This underscores the critical link between API security and LLM data integrity. Companies like Meta, Microsoft, Google, and VMware, despite their robust security practices, were still vulnerable to this type of API flaw.

ISMG further reminds us, “Tampering with training data to introduce vulnerabilities or biases is among the top 10 threats to large language models recognized by OWASP.”

Let’s break down the common types of data poisoning attacks.

  • Availability Attacks: These aim to degrade the overall performance of the model. Attackers might introduce noisy or irrelevant data, or manipulate labels (e.g., marking a spam email as harmless). The effect is a model that loses accuracy and struggles to make reliable predictions. An attacker could exploit exposed API tokens with write permissions to add misleading data to training sets, as seen in the recent Hugging Face example.
  • Targeted Attacks: In targeted attacks, the goal is to force the model to misclassify a specific type of input. For example, an attacker might train a facial recognition system to fail to identify a particular individual by feeding it poisoned data.
  • Backdoor Attacks: Perhaps the most insidious type of data poisoning, backdoor attacks embed hidden triggers within the model. An attacker might introduce seemingly normal images but with a specific pattern that, when recognized later, will cause the model to produce a desired, incorrect output.
  • Injection Flaws: Security vulnerabilities like SQL injection or code injection in the API could allow the hacker to manipulate data being submitted.
  • Insecure Data Transmission: Unencrypted data transfer between the API and data source could allow attackers to intercept and modify the training data in transit.

The API Connection

Here’s a breakdown of the specific connections between APIs and data poisoning risks in Large Language Models (LLMs):

LLMs Are Data Hungry: LLMs work by ingesting vast amounts of text and code data. The more diverse and high-quality this data is, the better the model becomes at understanding language, generating text, and performing various tasks. This dependency on data is the core connection to poisoning risks.

APIs as the Feeding Mechanism 

APIs often provide the essential pipeline to supply data to LLMs, especially in real-world applications. They allow you to:

  1. Train and Retrain LLMs: Initial model training involves massive datasets, and APIs are frequently used to channel this data. Additionally, LLMs can be periodically fine-tuned with new data through APIs.
  2. Real-time Inference: When an LLM is used to analyze a question, translate text, etc., that input is likely submitted through an API to be processed by the model and returned via the same API.

API Vulnerabilities Create Openings for Attackers 

If the APIs handling data flow to the LLM are insecure, attackers have a path to exploit:

  1. Authentication Issues: Pretending to be a legitimate data source to feed poisoned data.
  2. Authorization Problems: Modifying existing training data or injecting new malicious data.
  3. Input Validation Loopholes: Sending malformed data, code disguised as data, etc., to disrupt the LLM’s learning or decision making.

The Impact of Poisoning an LLM 

Successful data poisoning of an LLM can have far-reaching consequences:

  1. Degrading Performance: Reduced accuracy across various tasks as the model’s internal logic is corrupted.
  2. Bias and Discrimination: Poisoned data can skew the model’s results, potentially leading to discriminatory or harmful output.
  3. Embedded Backdoors: For targeted attacks, hidden triggers can be introduced, making the LLM produce a specific incorrect response whenever that trigger is presented.

Key Takeaway: Because of their reliance on data and the frequent use of APIs to interface with them, LLMs are inherently vulnerable to data poisoning attacks. 

How to Protect Against Data Poisoning

API Security Best Practices

Securing the APIs that feed data into AI models is a crucial line of defense against data poisoning. Prioritize the following:

  1. Authentication: Every API call should verify the identity of the user or system submitting data. Implement strong authentication mechanisms like multi-factor authentication or token-based systems.
  2. Strict Authorization: Define granular permissions for who/what can submit data and what data they can add or modify. Enforce these rules with access controls.
  3. Intelligent Rate Limiting: Intelligent rate limiting goes beyond fixed thresholds for API requests. It analyzes contextual information, including typical usage patterns, to dynamically adjust rate limits. It should be adaptive, considering typical usage patterns and adjusting thresholds dynamically to flag abnormal traffic surges. 
  4. Rigorous Input Validation: Treat all API input with scrutiny. Validate format, data types, and content against expected models. Reject unexpected payloads, prevent the injection of malicious code disguised as data, and sanitize input where possible.

Beyond the Basics: Context-Aware API Security

The complexity of API ecosystems demands a new approach to API security. Traditional solutions that rely on limited data points often fail to detect sophisticated threats, leaving your critical systems vulnerable.

To truly safeguard your APIs, you need a solution that analyzes the full context of your API environment, uncovering hidden risks and enabling proactive protection.

Traceable takes a fundamentally different approach to API security. By collecting and analyzing the deepest set of API data, both internally and externally, Traceable provides unparalleled insights into your API landscape. This comprehensive understanding, powered by the Traceable API Security Data Lake, enables the detection of even the most subtle attack attempts, as well as a wide range of other API threats and digital fraud.

Beyond core API security, Traceable empowers your teams with:

  • API Discovery and Posture Management: Continuous mapping of your entire API landscape, including shadow and rogue APIs, to eliminate blind spots.
  • Attack Detection and Threat Hunting: AI-powered analysis and deep data visibility for proactive security and investigation of unique threats.
  • Attack Protection: Real-time blocking of known and unknown attacks, including business logic abuse, and fraud.
  • API Security Testing: Proactive vulnerability discovery to prevent pushing insecure APIs into production.


Gain a deeper understanding of Context-Aware API Security with Traceable’s comprehensive whitepaper, “Context-Aware Security: The Imperative for API Protection.” Learn how this approach goes beyond traditional API security to protect your critical assets.

Context-Aware API Security: The Imperative for Complete API Protection

Context-Aware API Security: The Imperative for Complete API Protection



Dhar, Payal. “Protecting AI Models from ‘Data Poisoning.’” IEEE Spectrum, IEEE Spectrum, 29 Mar. 2023, spectrum.ieee.org/ai-cybersecurity-data-poisoning. 

“ML02:2023 Data Poisoning Attack.” OWASP Machine Learning Security Top Ten 2023 | ML02:2023 Data Poisoning Attack | OWASP Foundation, owasp.org/www-project-machine-learning-security-top-10/docs/ML02_2023-Data_Poisoning_Attack. Accessed 11 Mar. 2024. 

“Data Poisoning – A Security Threat in AI & Machine Learning.” Security Journal Americas, 7 Mar. 2024, securityjournalamericas.com/data-poisoning/.


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