The software trusts the hostname that is provided when performing a reverse DNS resolution on an IP address, without also performing forward resolution.
Time of Introduction
Architecture and Design
Applicable Platforms
Languages
All
Common Consequences
Scope
Effect
Access Control
Technical Impact: Gain privileges / assume
identity; Bypass protection
mechanism
Demonstrative Examples
Example 1
In the example below, an authorization decision is made on the
result of a reverse DNS lookup.
(Bad Code)
Example
Language: Java
InetAddress clientAddr = getClientInetAddr();
if (clientAddr != null &&
clientAddr.getHostName().equals("authorizedhost.authorizeddomain.com")
{
Filter does not properly check the result of a
reverse DNS lookup, which could allow remote attackers to bypass intended
access restrictions via DNS spoofing.
Description
