CAPEC Details
Name AJAX Footprinting
Likelyhood of attack Typical severity
High Low
Summary This attack utilizes the frequent client-server roundtrips in Ajax conversation to scan a system. While Ajax does not open up new vulnerabilities per se, it does optimize them from an attacker point of view. A common first step for an attacker is to footprint the target environment to understand what attacks will work. Since footprinting relies on enumeration, the conversational pattern of rapid, multiple requests and responses that are typical in Ajax applications enable an attacker to look for many vulnerabilities, well-known ports, network locations and so on. The knowledge gained through Ajax fingerprinting can be used to support other attacks, such as XSS.
Prerequisites The user must allow JavaScript to execute in their browser
Execution Flow
Step Phase Description Techniques
1 Explore [Send requests to the server and analyze responses] Using a browser or an automated tool, an attacker sends requests to a website and then captures the responses. Responses are analyzed for information on frameworks, architecture, and dependencies.
  • Use a browser to manually request pages and view the responses. Manually parse responses to find information on dependencies and underlying architecture
  • Use automated scripting to send one or multiple requests to a server and capture any responses. Parse responses from the server to identify any tags that may provide information about dependencies and underlying architecture.
Solutions Design: Use browser technologies that do not allow client side scripting. Implementation: Perform input validation for all remote content.
Related Weaknesses
CWE ID Description
CWE-20 Improper Input Validation
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-86 Improper Neutralization of Invalid Characters in Identifiers in Web Pages
CWE-96 Improper Neutralization of Directives in Statically Saved Code ('Static Code Injection')
CWE-113 Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting')
CWE-116 Improper Encoding or Escaping of Output
CWE-184 Incomplete List of Disallowed Inputs
CWE-348 Use of Less Trusted Source
CWE-692 Incomplete Denylist to Cross-Site Scripting
Related CAPECS
CAPEC ID Description
CAPEC-63 An adversary embeds malicious scripts in content that will be served to web browsers. The goal of the attack is for the target software, the client-side browser, to execute the script with the users' privilege level. An attack of this type exploits a programs' vulnerabilities that are brought on by allowing remote hosts to execute code and scripts. Web browsers, for example, have some simple security controls in place, but if a remote attacker is allowed to execute scripts (through injecting them in to user-generated content like bulletin boards) then these controls may be bypassed. Further, these attacks are very difficult for an end user to detect.
CAPEC-580 An adversary engages in active probing and exploration activities to determine security information about a remote target system. Often times adversaries will rely on remote applications that can be probed for system configurations.