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ID

CWE-290: Authentication Bypass by Spoofing

Weakness ID: 290
Abstraction: Base
Status: Incomplete
Presentation Filter:
+ Description

Description Summary

This attack-focused weakness is caused by improperly implemented authentication schemes that are subject to spoofing attacks.
+ Time of Introduction
  • Architecture and Design
  • Implementation
+ Common Consequences
ScopeEffect
Access Control

Technical Impact: Bypass protection mechanism; Gain privileges / assume identity

This weakness can allow an attacker to access resources which are not otherwise accessible without proper authentication.

+ Demonstrative Examples

Example 1

The following code authenticates users.

(Bad Code)
Example Language: Java 
String sourceIP = request.getRemoteAddr();
if (sourceIP != null && sourceIP.equals(APPROVED_IP)) {
authenticated = true;
}

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.

Example 2

Both of these examples check if a request is from a trusted address before responding to the request.

(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)==getTrustedAddress()) {
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);
outSock.receive(rp);
String in = new String(p.getData(),0, rp.getLength());
InetAddress clientIPAddress = rp.getAddress();
int port = rp.getPort();

if (isTrustedAddress(clientIPAddress) & secretKey.equals(in)) {
out = secret.getBytes();
DatagramPacket sp =new DatagramPacket(out,out.length, IPAddress, port); outSock.send(sp);
}
}

The code only verifies the address as stored in the request packet. An attacker can spoof this address, thus impersonating a trusted client

Example 3

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.

(Bad Code)
Example Language:
struct hostent *hp;struct in_addr myaddr;
char* tHost = "trustme.example.com";
myaddr.s_addr=inet_addr(ip_addr_string);

hp = gethostbyaddr((char *) &myaddr, sizeof(struct in_addr), AF_INET);
if (hp && !strncmp(hp->h_name, tHost, sizeof(tHost))) {
trusted = true;
} else {
trusted = false;
}
(Bad Code)
Example Language: Java 
String ip = request.getRemoteAddr();
InetAddress addr = InetAddress.getByName(ip);
if (addr.getCanonicalHostName().endsWith("trustme.com")) {
trusted = true;
}
(Bad Code)
Example Language: C# 
IPAddress hostIPAddress = IPAddress.Parse(RemoteIpAddress);
IPHostEntry hostInfo = Dns.GetHostByAddress(hostIPAddress);
if (hostInfo.HostName.EndsWith("trustme.com")) {
trusted = true;
}

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.

+ Observed Examples
ReferenceDescription
VOIP product allows authentication bypass using 127.0.0.1 in the Host header.
+ Relationships
NatureTypeIDNameView(s) this relationship pertains toView(s)
ChildOfWeakness ClassWeakness Class592Authentication Bypass Issues
Development Concepts (primary)699
Research Concepts (primary)1000
ChildOfCategoryCategory956SFP Secondary Cluster: Channel Attack
Software Fault Pattern (SFP) Clusters (primary)888
ParentOfWeakness VariantWeakness Variant291Reliance on IP Address for Authentication
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant293Using Referer Field for Authentication
Development Concepts (primary)699
Research Concepts (primary)1000
ParentOfWeakness VariantWeakness Variant350Reliance on Reverse DNS Resolution for a Security-Critical Action
Development Concepts (primary)699
Research Concepts (primary)1000
MemberOfViewView884CWE Cross-section
CWE Cross-section (primary)884
PeerOfWeakness BaseWeakness Base602Client-Side Enforcement of Server-Side Security
Research Concepts1000
CanAlsoBeWeakness BaseWeakness Base358Improperly Implemented Security Check for Standard
Research Concepts1000
+ Relationship Notes

This can be resultant from insufficient verification.

+ Taxonomy Mappings
Mapped Taxonomy NameNode IDFitMapped Node Name
PLOVERAuthentication bypass by spoofing
+ References
[REF-7] Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 3, "Spoofing and Identification", Page 72.. 1st Edition. Addison Wesley. 2006.
+ Content History
Submissions
Submission DateSubmitterOrganizationSource
PLOVERExternally Mined
Modifications
Modification DateModifierOrganizationSource
2008-07-01Sean EidemillerCigitalExternal
added/updated demonstrative examples
2008-07-01Eric DalciCigitalExternal
updated Time_of_Introduction
2008-09-08CWE Content TeamMITREInternal
updated Description, Relationships, Relationship_Notes, Taxonomy_Mappings
2009-07-27CWE Content TeamMITREInternal
updated Relationship_Notes
2011-06-01CWE Content TeamMITREInternal
updated Common_Consequences
2012-05-11CWE Content TeamMITREInternal
updated Common_Consequences, Demonstrative_Examples, Observed_Examples, References, Related_Attack_Patterns, Relationships
2013-07-17CWE Content TeamMITREInternal
updated Relationships
2014-02-18CWE Content TeamMITREInternal
updated Related_Attack_Patterns
2014-07-30CWE Content TeamMITREInternal
updated Demonstrative_Examples, Relationships

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Page Last Updated: January 18, 2017