Authentication Bypass by Spoofing
This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
The following examples help to illustrate the nature of this weakness and describe methods or techniques which can be used to mitigate the risk.
Note that the examples here are by no means exhaustive and any given weakness may have many subtle varieties, each of which may require different detection methods or runtime controls.
The following code authenticates users.
The authentication mechanism implemented relies on an IP address for source validation. If an attacker is able to spoof the IP, they may be able to bypass the authentication mechanism.
Both of these examples check if a request is from a trusted address before responding to the request.
The code only verifies the address as stored in the request packet. An attacker can spoof this address, thus impersonating a trusted client.
The following code samples use a DNS lookup in order to decide whether or not an inbound request is from a trusted host. If an attacker can poison the DNS cache, they can gain trusted status.
IP addresses are more reliable than DNS names, but they can also be spoofed. Attackers can easily forge the source IP address of the packets they send, but response packets will return to the forged IP address. To see the response packets, the attacker has to sniff the traffic between the victim machine and the forged IP address. In order to accomplish the required sniffing, attackers typically attempt to locate themselves on the same subnet as the victim machine. Attackers may be able to circumvent this requirement by using source routing, but source routing is disabled across much of the Internet today. In summary, IP address verification can be a useful part of an authentication scheme, but it should not be the single factor required for authentication.
Weaknesses in this category are related to the A07 category "Identification and Authentication Failures" in the OWASP Top Ten 2021.
Weaknesses in this category are related to authentication components of a system. Frequently these deal with the ability to verify that an entity is indeed who it clai...
Weaknesses in this category are related to the design and architecture of authentication components of the system. Frequently these deal with verifying the entity is i...
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