CWE-941: Incorrectly Specified Destination in a Communication Channel

How it's found

Incorrectly Specified Destination in a Communication Channel is typically found by tracing untrusted input from where it enters the system to the point where it is used without the check or neutralization this weakness describes, combining manual code review with dynamic testing.

Attackers at the destination may be able to spoof trusted servers to steal data or cause a denial of service. There are at least two distinct weaknesses that can cause the product to communicate with an unintended destination:If the product allows an attacker to control which destination is specified, then the attacker can cause it to connect to an untrusted or malicious destination. For example, because UDP is a connectionless protocol, UDP packets can be spoofed by specifying a false source address in the packet; when the server receives the packet and sends a reply, it will specify a destination by using the source of the incoming packet - i.e., the false source. The server can then be tricked into sending traffic to the wrong host, which is effective for hiding the real source of an attack and for conducting a distributed denial of service (DDoS). As another example, server-side request forgery (SSRF) and XML External Entity (XXE) can be used to trick a server into making outgoing requests to hosts that cannot be directly accessed by the attacker due to firewall restrictions. If the product incorrectly specifies the destination, then an attacker who can control this destination might be able to spoof trusted servers. While the most common occurrence is likely due to misconfiguration by an administrator, this can be resultant from other weaknesses. For example, the product might incorrectly parse an e-mail or IP address and send sensitive data to an unintended destination. As another example, an Android application may use a "sticky broadcast" to communicate with a receiver for a particular application, but since sticky broadcasts can be processed by *any* receiver, this can allow a malicious application to access restricted data that was only intended for a different application.

Consequences

• Gain Privileges or Assume Identity, Varies by Context, Bypass Protection Mechanism: An attacker can access any functionality that is inadvertently accessible to the source.

Where this fits in a TurboPentest engagement

This weakness is not covered by the automated black-box pentest. IntegSec pentesters cover it in a manual engagement.

Frequently asked questions

Related CWEs

• Class weakness
  CWE-923: Improper Restriction of Communication Channel to Intended Endpoints