Working with Scans

Configuring URL Rewrite Rules

This document is for:
Invicti Standard, Invicti Enterprise On-Premises, Invicti Enterprise On-Demand

Web application developers employ URL Rewrite Rules to hide parameters within the URL path structure. This practice facilitates comprehensive indexing by search engines while presenting URLs to web browsers in a user-friendly format. For example, when navigating an online hardware store, the URL typically appears as

Through a URL rewrite rule, the web server transforms this URL into a specific format, such as, enabling retrieval of data from the backend database for displaying tool details to visitors.

In this scenario, the subdirectory ("/tools") in the initial URL functions as a parameter within the library.php file, accommodating inputs like the tool name ("hammer"). Invicti conducts scans by sending standard HTTP requests to simulate attacker behavior, ensuring the web application accepts such requests and appropriately scans all parameters within the URLs. Furthermore, it can scan pages with multiple parameters in the URL.

For more information on how URL Rewrite rules work in Invicti, refer to How Invicti handles URL rewriting.

NOTE: Invicti automatically detects URL rewrites on the target website using heuristic methods. Additionally, it offers automatic configuration of settings. Nevertheless, manual configuration of URL Rewrite Rules, as detailed in this document, can enhance the efficiency of the scan.

How to Configure URL Rewrite Rules in Invicti Enterprise

  1. From the main menu, select Scans > New Scan.
  2. Specify the Target URL and Scan Profile.
  3. In the Scan Settings section, select URL Rewrite.

  1. In the URL Rewrite Mode, select from the options: None, Heuristic, or Custom.
  • Heuristic is the default mode and automatically populates these fields:
  • Root Path Maximum Dynamic Signatures
  • Sub Path Maximum Dynamic Signatures
  • Block Separators
  • Analyzable Extensions

  • Choosing None applies no rules:

  • If Custom is selected:
  • Enable or disable Heuristic URL Rewrite Detection to determine additional rules automatically; when this option is selected, Invicti tries to automatically determine other URL Rewrite rules as well. If enabled, both Custom and Heuristic rules will apply. If disabled, only the Custom rules will apply.

  • Specify new rules by pressing New and entering relevant information in the Placeholder Pattern and RegEx Pattern fields.

  1. Optionally, create exclusions by clicking New from the Exclusions section and entering relevant information in the Excluded Path and Is Regex fields.

  1. Continue populating the Scan Settings as required and click Launch.

How to Configure URL Rewrite Rules in Invicti Standard

  1. Open Invicti Standard and click New
  2. On the Start a New Website or Web Service Scan window, specify the Target URL and click the down arrow to expand the Options menu

  1. Click on the URL Rewrite option

  1. The Heuristic mode is the default option. Change this to Custom.

  1. There are two ways to add new rules:
  1. Manually
  2. Using the build-in wizard

NOTE: To manually configure the URL Rewrite rules without utilizing the wizard, you can directly populate the Placeholder Pattern and RegEx Pattern input fields by clicking on them.

Adding URL Rewrite Rules manually

  1. To configure the URL Rewrite rules manually without using the wizard, simply input values directly into the Placeholder Pattern and RegEx Pattern fields by clicking on them.

If your website URLs contain encoded values, it is imperative to specify the decoded values consistently.

For instance, consider a Website URL In this case, the correct URL rewrite rule should reflect the decoded characters, such as{firstname}-{lastname}.

Conversely, using encoded characters in the rewrite rule, as in{firstname}%2d{lastname}, is incorrect and should be avoided.

After filling in the required information, proceed to step 10 outlined below.

Adding URL Rewrite Rules using the wizard

  1. Click New to specify new rules.

  1. In the wizard window, fill in the URL and click Next.

  1. Using the checkboxes, select the URL Rewrite Parameters, specify the Parameter Type, and type the Parameter Name.

Specifying the correct parameter type enhances scan accuracy. For instance, in the pattern '/{PARAM}/{ID}', '{PARAM}' denotes the parameter and '{ID}' its value. Without specifying a parameter type, defaulting to 'Any', both URLs match:


However, this broad matching can lead to inaccurate results. For example, '/products/date.js' might be mistaken as a product parameter value, causing some files to be overlooked. Setting the parameter type to 'Integer' resolves this, ensuring Invicti scans only integers. Consequently, anomalies like '/product/date.js' are correctly identified as files.

Finish to generate the placeholder pattern and regular expression.

  1. Select the Enable Heuristic Rule Detection checkbox. The scanner still tries to automatically detect any additional URL Rewrites on the target website and use them in conjunction with the ones you configured.

  1. To exclude certain URLs from the URL Rewrite Detection, select Exclusions.

  1.  The Excluded Paths dialog is displayed. Complete the Excluded Path and click Save on the dialog box.

  1. The Exclusions counter changes to acknowledge the newly added rule exclusion.

  1. If necessary, click Test to execute the URL Rewrite Rules. During the testing phase, input an example URL in the field adjacent to the Test button.

  1. Click Start Scan to start the scan immediately, or use the down arrow to schedule the scan.

Challenges Associated with URL Rewrite Rules

This table outlines and elucidates the potential issues encountered by automated web vulnerability scanners when scanning websites utilizing URL Rewrite Rules.




Parameters within URLs are overlooked during scanning due to misidentification

Web scanners struggle with URL rewriting, mistaking parameters for directories and leaving them unscanned.

For example, the URL is misinterpreted, as "tools" and "hammer" are considered directories instead of parameters and values, respectively.

Extended scan

Extended scans can lead to inaccurate results and software crashes. For instance, if a web vulnerability scanner fails to recognize parameters and values in URLs, it may treat each item in a tool database as a separate page to crawl and scan. Inadequate handling of memory problems and exceptions may further contribute to crashes, resulting in lost results and wasted time.

Inadequate handling of memory problems and other exceptions in your scanner may lead to crashes, resulting in lost results and wasted time.

Failure to configure URL rewrite rules in Invicti leads to heuristic pattern identification, limiting scans to prevent prolonged durations and inaccurate outcomes.

Setting up URL rewrite rules presents a challenging task

Commercial web vulnerability scanners often offer configuration options to identify parameters within URLs due to the prevalence of URL rewrite technology in web applications. However, users face challenges such as complex setup processes, the need for knowledge in writing regular expressions, and requiring access to web server configuration files.

Configuring URL rewrite rules is particularly challenging for users without deep understanding of the web application or direct access to configuration files, making it a time-consuming task even for those with expertise.

Web applications are not properly scanned for vulnerabilities

After configuring URL rewrite rules in your web vulnerability scanner, additional limitations emerge in scanning the web application.

Web applications, as a security measure, reject HTTP requests that are already 'translated', like This is default behavior for .NET web applications, which worsens the issue when scanning MVC web applications due to their distinct URL rewriting approach.

Invicti scans MVC web applications, but numerous other vulnerability scanners fail to do so, even with configured URL rewrite rules.

After setting up URL rewrite rules in your scanner, it sends translated query HTTP requests. Despite the security scanner reporting a successful scan, most HTTP requests are denied, leaving parameters in URLs unscanned and creating a misleading sense of security.

URL Rewrite Fields

This table lists and describes the fields in the URL Rewrite tab.



Root Path Max Dynamic Signatures

If a URL block in the root path contains more items than this limit, it will be identified as a URL rewrite parameter. It must be between 1 and 10,000.

This field is displayed only in the Heuristic tab.

Sub Path Dynamic Signatures

If a URL block in the subpath contains more items than this limit, it will be identified as a URL rewrite parameter. It must be between 1 and 10,000.

This field is displayed only in the Heuristic tab.

Block Separators

Enter separators to use to split the URL into blocks.

This field is displayed only in the Heuristic tab.

Analyzable Extensions

If the URL contains a file extension, it will be analyzed only if the respective extension is in this list.

This field is displayed only in the Heuristic tab.

Enable Heuristic URL Rewrite detection

Invicti will try to automatically detect other URL rewrite rules if this option is set.

This field is displayed only in the Custom tab.

Placeholder Pattern

This contains the relative path with placeholders for URL rewrite parameters.

This field is displayed only in the Custom tab.

RegEx Pattern

This is a regular expression used for matching the URL rewrite parameters.

This field is displayed only in the Custom tab.

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