This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
View on MITREThis weakness can allow an attacker to access resources which are not otherwise accessible without proper authentication.
No mitigation information available for this CWE.
No detection method information available for this CWE.
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.
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.
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.
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.
S-bus functionality in a home automation product performs access control using an IP allowlist, which can be bypassed by a forged IP address.
View DetailsVOIP product allows authentication bypass using 127.0.0.1 in the Host header.
View DetailsCWE-290: Authentication Bypass by Spoofing is a Common Weakness Enumeration (CWE) entry maintained by MITRE. This attack-focused weakness is caused by incorrectly implemented authentication schemes that are subject to spoofing attacks.
If exploited, CWE-290 (Authentication Bypass by Spoofing) it can compromise Access Control, leading to outcomes such as Bypass Protection Mechanism and Gain Privileges or Assume Identity.
MITRE documents real CVEs mapped to CWE-290, including CVE-2022-30319 and CVE-2009-1048. You can look up the full details of each CVE, including CVSS scores and remediation guidance, on our CVE Lookup tool.
A CWE (Common Weakness Enumeration) like CWE-290 describes a category of software weakness — the underlying flaw type. A CVE (Common Vulnerabilities and Exposures) identifies a specific, real-world vulnerability in a particular product. In short, a CWE is the kind of mistake, and a CVE is an instance of that mistake being found in software.