Trusting Self-reported IP Address
Compound Element ID: 291 (Compound Element Variant: Composite)Status: Incomplete
+ Description

Description Summary

The use of IP addresses as authentication is flawed and can easily be spoofed by malicious users.

Extended Description

As IP addresses can be easily spoofed, they do not constitute a valid authentication mechanism. Alternate methods should be used if significant authentication is necessary.

+ Time of Introduction
  • Architecture and Design
+ Applicable Platforms



+ Common Consequences

Malicious users can fake authentication information, impersonating any IP address.

+ Likelihood of Exploit


+ Demonstrative Examples

Example 1

(Bad Code)
Example Languages: C and C++ 
sd = socket(AF_INET, SOCK_DGRAM, 0);
serv.sin_family = AF_INET;
serv.sin_addr.s_addr = htonl(INADDR_ANY);
servr.sin_port = htons(1008);
bind(sd, (struct sockaddr *) & serv, sizeof(serv));
while (1) {

memset(msg, 0x0, MAX_MSG);
clilen = sizeof(cli);
if (inet_ntoa(cli.sin_addr)==...) n = recvfrom(sd, msg, MAX_MSG, 0, (struct sockaddr *) & cli, &clilen);
(Bad Code)
Example Language: Java 
while(true) {
DatagramPacket rp=new DatagramPacket(rData,rData.length);
String in = new String(p.getData(),0, rp.getLength());
InetAddress IPAddress = rp.getAddress();
int port = rp.getPort();
if ((rp.getAddress()==...) & (in==...)) {

out = secret.getBytes();
DatagramPacket sp =new DatagramPacket(out,out.length, IPAddress, port); outSock.send(sp);
+ Potential Mitigations

Phase: Architecture and Design

Use other means of identity verification that cannot be simply spoofed. Possibilities include a username/password or certificate.

+ Weakness Ordinalities
(where the weakness is typically related to the presence of some other weaknesses)
+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
RequiresWeakness BaseWeakness Base348Use of Less Trusted Source
Research Concepts1000
RequiresWeakness BaseWeakness Base471Modification of Assumed-Immutable Data (MAID)
Research Concepts1000
ChildOfWeakness BaseWeakness Base290Authentication Bypass by Spoofing
Development Concepts (primary)699
Research Concepts (primary)1000
PeerOfWeakness VariantWeakness Variant292Trusting Self-reported DNS Name
Research Concepts1000
PeerOfWeakness VariantWeakness Variant293Using Referer Field for Authentication
Research Concepts1000
+ Causal Nature


+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
CLASPTrusting self-reported IP address
+ Related Attack Patterns
CAPEC-IDAttack Pattern Name
(CAPEC Version: 1.4)
4Using Alternative IP Address Encodings
+ Content History
Submission DateSubmitterOrganizationSource
CLASPExternally Mined
Modification DateModifierOrganizationSource
2008-09-08CWE Content TeamMITREInternal
updated Common Consequences, Relationships, Other Notes, Taxonomy Mappings, Weakness Ordinalities