Weakness ID: 350
Vulnerability Mapping: ALLOWED This CWE ID may be used to map to real-world vulnerabilitiesAbstraction: Variant Variant - a weakness that is linked to a certain type of product, typically involving a specific language or technology. More specific than a Base weakness. Variant level weaknesses typically describe issues in terms of 3 to 5 of the following dimensions: behavior, property, technology, language, and resource.
Description
The product performs reverse DNS resolution on an IP address to obtain the hostname and make a security decision, but it does not properly ensure that the IP address is truly associated with the hostname.
Extended Description
Since DNS names can be easily spoofed or misreported, and it may be difficult for the product to detect if a trusted DNS server has been compromised, DNS names do not constitute a valid authentication mechanism.
When the product performs a reverse DNS resolution for an IP address, if an attacker controls the DNS server for that IP address, then the attacker can cause the server to return an arbitrary hostname. As a result, the attacker may be able to bypass authentication, cause the wrong hostname to be recorded in log files to hide activities, or perform other attacks.
Attackers can spoof DNS names by either (1) compromising a DNS server and modifying its records (sometimes called DNS cache poisoning), or (2) having legitimate control over a DNS server associated with their IP address.
Common Consequences
This table specifies different individual consequences
associated with the weakness. The Scope identifies the application security area that is
violated, while the Impact describes the negative technical impact that arises if an
adversary succeeds in exploiting this weakness. The Likelihood provides information about
how likely the specific consequence is expected to be seen relative to the other
consequences in the list. For example, there may be high likelihood that a weakness will be
exploited to achieve a certain impact, but a low likelihood that it will be exploited to
achieve a different impact.
| Impact | Details |
|---|---|
|
Gain Privileges or Assume Identity; Bypass Protection Mechanism |
Scope: Access Control
Malicious users can fake authentication information by providing false DNS information. |
Potential Mitigations
| Phase(s) | Mitigation |
|---|---|
|
Architecture and Design |
Use other means of identity verification that cannot be simply spoofed. Possibilities include a username/password or certificate. |
|
Implementation |
Perform proper forward and reverse DNS lookups to detect DNS spoofing. |
Relationships
This table shows the weaknesses and high level categories that are related to this
weakness. These relationships are defined as ChildOf, ParentOf, MemberOf and give insight to
similar items that may exist at higher and lower levels of abstraction. In addition,
relationships such as PeerOf and CanAlsoBe are defined to show similar weaknesses that the user
may want to explore.
Relevant to the view "Research Concepts" (View-1000)
| Nature | Type | ID | Name |
|---|---|---|---|
| ChildOf |
Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
|
290 | Authentication Bypass by Spoofing |
| ChildOf |
Base - a weakness that is still mostly independent of a resource or technology, but with sufficient details to provide specific methods for detection and prevention. Base level weaknesses typically describe issues in terms of 2 or 3 of the following dimensions: behavior, property, technology, language, and resource.
|
807 | Reliance on Untrusted Inputs in a Security Decision |
| CanPrecede |
Class - a weakness that is described in a very abstract fashion, typically independent of any specific language or technology. More specific than a Pillar Weakness, but more general than a Base Weakness. Class level weaknesses typically describe issues in terms of 1 or 2 of the following dimensions: behavior, property, and resource.
|
923 | Improper Restriction of Communication Channel to Intended Endpoints |
Modes
Of Introduction
The different Modes of Introduction provide information
about how and when this
weakness may be introduced. The Phase identifies a point in the life cycle at which
introduction
may occur, while the Note provides a typical scenario related to introduction during the
given
phase.
| Phase | Note |
|---|---|
| Architecture and Design |
Applicable Platforms
This listing shows possible areas for which the given
weakness could appear. These
may be for specific named Languages, Operating Systems, Architectures, Paradigms,
Technologies,
or a class of such platforms. The platform is listed along with how frequently the given
weakness appears for that instance.
| Languages |
Class: Not Language-Specific (Undetermined Prevalence) |
Demonstrative Examples
Example 1
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: C
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.
Example 2
In these examples, a connection is established if a request is made by a trusted host.
(bad code)
Example Language: 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);
h=gethostbyname(inet_ntoa(cliAddr.sin_addr));
if (h->h_name==...) 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 IPAddress = rp.getAddress();
int port = rp.getPort();
if ((rp.getHostName()==...) & (in==...)) {
out = secret.getBytes();
DatagramPacket sp =new DatagramPacket(out,out.length, IPAddress, port);
outSock.send(sp);
}
}
These examples check if a request is from a trusted host before responding to a request, but the code only verifies the hostname as stored in the request packet. An attacker can spoof the hostname, thus impersonating a trusted client.
Selected Observed
Examples
Note: this is a curated list of examples for users to understand the variety of ways in which this weakness can be introduced. It is not a complete list of all CVEs that are related to this CWE entry.
| Reference | Description |
|---|---|
|
Does not do double-reverse lookup to prevent DNS spoofing. |
|
|
Does not verify reverse-resolved hostnames in DNS. |
|
|
Authentication bypass using spoofed reverse-resolved DNS hostnames. |
|
|
Authentication bypass using spoofed reverse-resolved DNS hostnames. |
|
|
Filter does not properly check the result of a reverse DNS lookup, which could allow remote attackers to bypass intended access restrictions via DNS spoofing. |
|
|
Reverse DNS lookup used to spoof trusted content in intermediary. |
|
|
Product records the reverse DNS name of a visitor in the logs, allowing spoofing and resultant XSS. |
Weakness Ordinalities
| Ordinality | Description |
|---|---|
|
Primary |
(where the weakness exists independent of other weaknesses) |
Detection
Methods
| Method | Details |
|---|---|
|
Automated Static Analysis |
Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.) Effectiveness: High |
Memberships
This MemberOf Relationships table shows additional CWE Categories and Views that
reference this weakness as a member. This information is often useful in understanding where a
weakness fits within the context of external information sources.
| Nature | Type | ID | Name |
|---|---|---|---|
| MemberOf |  Category - a CWE entry that contains a set of other entries that share a common characteristic. |
949 | SFP Secondary Cluster: Faulty Endpoint Authentication |
| MemberOf | Category - a CWE entry that contains a set of other entries that share a common characteristic. |
1396 | Comprehensive Categorization: Access Control |
| MemberOf | Category - a CWE entry that contains a set of other entries that share a common characteristic. |
1442 | OWASP Top Ten 2025 Category A07:2025 - Authentication Failures |
Vulnerability Mapping Notes
| Usage |
ALLOWED
(this CWE ID may be used to map to real-world vulnerabilities) |
| Reason | Acceptable-Use |
|
Rationale |
This CWE entry is at the Variant level of abstraction, which is a preferred level of abstraction for mapping to the root causes of vulnerabilities. |
|
Comments |
Carefully read both the name and description to ensure that this mapping is an appropriate fit. Do not try to 'force' a mapping to a lower-level Base/Variant simply to comply with this preferred level of abstraction. |
Notes
Taxonomy
Mappings
| Mapped Taxonomy Name | Node ID | Fit | Mapped Node Name |
|---|---|---|---|
| PLOVER | Improperly Trusted Reverse DNS | ||
| CLASP | Trusting self-reported DNS name | ||
| Software Fault Patterns | SFP29 | Faulty endpoint authentication |
References
| [REF-18] |
Secure Software, Inc.. "The CLASP Application Security Process". 2005.
<https://cwe.mitre.org/documents/sources/TheCLASPApplicationSecurityProcess.pdf>. (URL validated: 2024-11-17) |
| [REF-44] | Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 15: Not Updating Easily." Page 231. McGraw-Hill. 2010. |
| [REF-44] | Michael Howard, David LeBlanc and John Viega. "24 Deadly Sins of Software Security". "Sin 24: Trusting Network Name Resolution." Page 361. McGraw-Hill. 2010. |
| [REF-62] | Mark Dowd, John McDonald and Justin Schuh. "The Art of Software Security Assessment". Chapter 16, "DNS Spoofing", Page 1002. 1st Edition. Addison Wesley. 2006. |
Content
History
| Submissions |
|||
|---|---|---|---|
| Submission Date | Submitter | Organization | |
|
2006-07-19
(CWE Draft 3, 2006-07-19) |
PLOVER | ||
 Modifications |
|||
| Modification Date | Modifier | Organization | |
|
2025-12-11
(CWE 4.19, 2025-12-11) |
CWE Content Team | MITRE | |
| updated Relationships, Weakness_Ordinalities | |||
|
2023-06-29
(CWE 4.12, 2023-06-29) |
CWE Content Team | MITRE | |
| updated Mapping_Notes | |||
|
2023-04-27
(CWE 4.11, 2023-04-27) |
CWE Content Team | MITRE | |
| updated Detection_Factors, Relationships | |||
|
2023-01-31
(CWE 4.10, 2023-01-31) |
CWE Content Team | MITRE | |
| updated Description | |||
|
2022-10-13
(CWE 4.9, 2022-10-13) |
CWE Content Team | MITRE | |
| updated Relationships | |||
|
2021-03-15
(CWE 4.4, 2021-03-15) |
CWE Content Team | MITRE | |
| updated Demonstrative_Examples | |||
|
2020-02-24
(CWE 4.0, 2020-02-24) |
CWE Content Team | MITRE | |
| updated References, Relationships | |||
|
2017-11-08
(CWE 3.0, 2017-11-08) |
CWE Content Team | MITRE | |
| updated Demonstrative_Examples, Relationships | |||
|
2017-05-03
(CWE 2.11, 2017-05-05) |
CWE Content Team | MITRE | |
| updated Related_Attack_Patterns | |||
|
2014-07-30
(CWE 2.8, 2014-07-31) |
CWE Content Team | MITRE | |
| updated Demonstrative_Examples, Relationships, Taxonomy_Mappings | |||
|
2014-02-18
(CWE 2.6, 2014-02-19) |
CWE Content Team | MITRE | |
| updated Description, Relationships | |||
|
2013-07-17
(CWE 2.5, 2013-07-17) |
CWE Content Team | MITRE | |
| updated Applicable_Platforms, Common_Consequences, Demonstrative_Examples, Description, Maintenance_Notes, Name, Potential_Mitigations, References, Relationships, Taxonomy_Mappings, Type | |||
|
2013-06-23
(CWE 2.5, 2013-07-17) |
CWE Content Team | MITRE | |
| CWE-247 and CWE-292 deprecated and merged into CWE-350 to address duplicates. | |||
|
2012-05-11
(CWE 2.2, 2012-05-15) |
CWE Content Team | MITRE | |
| updated Related_Attack_Patterns, Relationships | |||
|
2011-06-01
(CWE 1.13, 2011-06-01) |
CWE Content Team | MITRE | |
| updated Common_Consequences | |||
|
2010-09-27
(CWE 1.10, 2010-09-27) |
CWE Content Team | MITRE | |
| updated Potential_Mitigations | |||
|
2009-05-27
(CWE 1.4, 2009-05-27) |
CWE Content Team | MITRE | |
| updated Relationships | |||
|
2008-09-08
(CWE 1.0, 2008-09-09) |
CWE Content Team | MITRE | |
| updated Relationships, Taxonomy_Mappings | |||
|
2008-07-01
(CWE 1.0, 2008-09-09) |
Sean Eidemiller | Cigital | |
| added/updated demonstrative examples | |||
| Previous Entry Names |
|||
| Change Date | Previous Entry Name | ||
| 2013-07-17 | Improperly Trusted Reverse DNS | ||