Rate Limit Bypass

What is Rate Limiting?

Rate limiting is an access control mechanism that limits the number of requests a user, IP address, or account can make to a web service, API, or website within a certain period. This helps prevent server overload and protects against malicious activities like Denial of Service (DoS) attacks, which can cause system failures by overwhelming it with a high volume of requests.

What is Rate Limit Bypass?

Rate limit bypass is a technique used by attackers to circumvent these request restrictions, allowing them to send significantly more requests than the system allows, effectively ignoring the rate limiting settings. This can result in excessive server load, disruptions, and enable automated attacks, such as login attempts or data scraping.

Why is Rate Limit Bypass Dangerous?

Rate limit bypass introduces the following risks:

1. System Overload. When requests exceed normal limits, servers may struggle to process them, reducing service performance.
2. Malicious Attacks. Attackers can use rate limit bypass to engage in mass data scraping, spam, brute-force attacks, DDoS attacks, and other malicious actions targeting websites.
3. Data Privacy Violations. Without request limits, attackers can gain access to large amounts of data within a short time, which could compromise privacy.

Methods for Rate Limit Bypass

1. Changing IP Addresses. Attackers often use VPNs, proxy servers, or anonymizers to continuously change their IP address. When rate limiting is applied per IP address, this tactic enables attackers to bypass restrictions and send more requests.
2. Using Multiple Accounts. If rate limits are set per account, attackers can create numerous accounts, enabling them to send far more requests than one account would allow.
3. Delaying Requests. Some bypass methods involve spacing out requests to avoid exceeding rate limits quickly. Instead of sending many requests all at once, attackers add pauses to make the bypass less noticeable.
4. Manipulating HTTP Headers. Some rate limiting systems rely on HTTP headers, such as User-Agent or Referer, to identify request sources. Modifying or spoofing headers can help attackers avoid detection and blocking.
5. Using Dynamic Access Tokens. Systems that rely on access tokens (such as OAuth) may limit access per token. Attackers may frequently change or refresh tokens to bypass such limitations.

How to Protect a System from Rate Limit Bypass

1. User Identification by Unique Attributes. Using resilient identification methods, such as fingerprinting or multi-factor authentication, makes it harder for attackers to bypass rate limits.
2. Using CAPTCHA. Adding CAPTCHA to high-risk pages limits automated requests, making it more difficult to carry out attacks.
3. Monitoring for Anomalous Behavior. Detecting unusual behaviors indicating rate limit bypass can trigger automatic blocking of suspicious requests.
4. Account- and IP-Level Rate Limiting. Applying combined limits at both the account and IP levels significantly increases system security.
5. Token Rotation and Dynamic Rate Limits. Implementing dynamic rate limits with token updates reduces the effectiveness of bypass techniques.