CAPEC-34: HTTP Response Splitting

Detailed Stable 严重程度: High 攻击可能性: Medium

CAPEC版本: 3.9

更新日期: 2023-01-24

攻击模式描述

执行流程

步骤 1 Explore

[Survey network to identify target] The adversary performs network reconnaissance by monitoring relevant traffic to identify the network path and parsing of the HTTP messages with the goal of identifying potential targets

技术:
  • Scan networks to fingerprint HTTP infrastructure and monitor HTTP traffic to identify HTTP network path with a tool such as a Network Protocol Analyzer.
步骤 1 Experiment

[Identify vulnerabilities in targeted HTTP infrastructure and technologies] The adversary sends a variety of benign/ambiguous HTTP requests to observe responses from HTTP infrastructure in order to identify differences/discrepancies in the interpretation and parsing of HTTP requests by examining supported HTTP protocol versions, HTTP headers, syntax checking and input filtering.

步骤 2 Experiment

[Cause differential HTTP responses by experimenting with identified HTTP Request vulnerabilities] The adversary sends maliciously crafted HTTP request to back-end HTTP infrastructure to inject adversary data (in the form of HTTP headers with custom strings and embedded web scripts and objects) into HTTP responses (intended for intermediary and/or front-end client/victim HTTP agents communicating with back-end HTTP infrastructure) for the purpose of interfering with the parsing of HTTP responses by intermediary and front-end client/victim HTTP agents. The intended consequences of the malicious HTTP request and the subsequent adversary injection and manipulation of HTTP responses to intermediary and front-end client/victim HTTP agents, will be observed to confirm applicability of identified vulnerabilities in the adversary's plan of attack.

技术:
  • Continue the monitoring of HTTP traffic.
  • Follow an unrecognized (sometimes a RFC compliant) HTTP header with a subsequent HTTP request to potentially cause the HTTP request to be ignored and interpreted as part of the preceding HTTP request.
步骤 1 Exploit

[Perform HTTP Response Splitting attack] Using knowledge discovered in the experiment section above, smuggle a message to cause one of the consequences.

技术:
  • Leverage techniques identified in the Experiment Phase.

前提条件

  • A vulnerable or compromised server or domain/site capable of allowing adversary to insert/inject malicious content that will appear in the server's response to target HTTP agents (e.g., proxies and users' web browsers).
  • Differences in the way the two HTTP agents parse and interpret HTTP requests and its headers.
  • HTTP headers capable of being user-manipulated.
  • HTTP agents running on HTTP/1.0 or HTTP/1.1 that allow for Keep Alive mode, Pipelined queries, and Chunked queries and responses.

所需技能

Medium Detailed knowledge on HTTP protocol: request and response messages structure and usage of specific headers.
Medium Detailed knowledge on how specific HTTP agents receive, send, process, interpret, and parse a variety of HTTP messages and headers.
Medium Possess knowledge on the exact details in the discrepancies between several targeted HTTP agents in path of an HTTP message in parsing its message structure and individual headers.

所需资源

  • Tools capable of monitoring HTTP messages, and crafting malicious HTTP messages and/or injecting malicious content into HTTP messages.

后果影响

影响范围: Confidentiality Integrity Availability

技术影响: Execute Unauthorized Commands

影响范围: Confidentiality Access Control Authorization

技术影响: Gain Privileges

影响范围: Integrity

技术影响: Modify Data

缓解措施

Design: evaluate HTTP agents prior to deployment for parsing/interpretation discrepancies.

Configuration: front-end HTTP agents notice ambiguous requests.

Configuration: back-end HTTP agents reject ambiguous requests and close the network connection.

Configuration: Disable reuse of back-end connections.

Configuration: Use HTTP/2 for back-end connections.

Configuration: Use the same web server software for front-end and back-end server.

Implementation: Utilize a Web Application Firewall (WAF) that has built-in mitigation to detect abnormal requests/responses.

Configuration: Install latest vendor security patches available for both intermediary and back-end HTTP infrastructure (i.e. proxies and web servers)

Configuration: Ensure that HTTP infrastructure in the chain or network path utilize a strict uniform parsing process.

Implementation: Utilize intermediary HTTP infrastructure capable of filtering and/or sanitizing user-input.

分类映射

分类名称 条目ID 条目名称
WASC 25 HTTP Response Splitting
关键信息

CAPEC ID: CAPEC-34

抽象级别: Detailed

状态: Stable

典型严重程度: High

攻击可能性: Medium

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