CAPEC-275

Detailed Abstraction Level
Meta — Very abstract, high-level category
Standard — Specific enough to understand
Detailed — Tied to specific technique Draft MITRE CAPEC Status
Stable — Fully reviewed and complete
Draft — Under development
Incomplete — Partially defined
Deprecated — No longer recommended
Obsolete — Replaced by another CAPEC Likelihood: High Severity: Very High
DNS Rebinding

Description

An adversary serves content whose IP address is resolved by a DNS server that the adversary controls. After initial contact by a web browser (or similar client), the adversary changes the IP address to which its name resolves, to an address within the target organization that is not publicly accessible. This allows the web browser to examine this internal address on behalf of the adversary.

Prerequisites

The target browser must access content server from the adversary controlled DNS name. Web advertisements are often used for this purpose. The target browser must honor the TTL value returned by the adversary and re-resolve the adversary's DNS name after initial contact.

Mitigations

Design: IP Pinning causes browsers to record the IP address to which a given name resolves and continue using this address regardless of the TTL set in the DNS response. Unfortunately, this is incompatible with the design of some legitimate sites.

Implementation: Reject HTTP request with a malicious Host header.

Implementation: Employ DNS resolvers that prevent external names from resolving to internal addresses.

Skills Required

[Medium] Setup DNS server and the adversary's web server. Write a malicious script to allow the victim to connect to the web server.