CWE-307: Improper Restriction of Excessive Authentication Attempts
Weakness ID: 307
Vulnerability Mapping:ALLOWEDThis CWE ID may be used to map to real-world vulnerabilities Abstraction:
BaseBase - 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.
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Description
The product does not implement sufficient measures to prevent multiple failed authentication attempts within a short time frame.
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
Bypass Protection Mechanism
Scope: Access Control
An attacker could perform an arbitrary number of authentication attempts using different passwords, and eventually gain access to the targeted account using a brute force attack.
Potential Mitigations
Phase(s)
Mitigation
Architecture and Design
Common protection mechanisms include:
Disconnecting the user after a small number of failed attempts
Implementing a timeout
Locking out a targeted account
Requiring a computational task on the user's part.
Architecture and Design
Strategy: Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
Consider using libraries with authentication capabilities such as OpenSSL or the ESAPI Authenticator. [REF-45]
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
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.
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.
Relevant to the view "Weaknesses for Simplified Mapping of Published Vulnerabilities" (View-1003)
Nature
Type
ID
Name
ChildOf
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.
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
COMMISSION: This weakness refers to an incorrect design related to an architectural security tactic.
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
In January 2009, an attacker was able to gain administrator access to a Twitter server because the server did not restrict the number of login attempts [REF-236]. The attacker targeted a member of Twitter's support team and was able to successfully guess the member's password using a brute force attack by guessing a large number of common words. After gaining access as the member of the support staff, the attacker used the administrator panel to gain access to 33 accounts that belonged to celebrities and politicians. Ultimately, fake Twitter messages were sent that appeared to come from the compromised accounts.
However, there is no limit on parallel connections, so this does not increase the amount of time an attacker needs to complete an attack.
Example 4
In the following C/C++ example the validateUser method opens a socket connection, reads a username and password from the socket and attempts to authenticate the username and password.
(bad code)
Example Language: C
int validateUser(char *host, int port) {
int socket = openSocketConnection(host, port); if (socket < 0) {
printf("Unable to open socket connection"); return(FAIL);
}
int isValidUser = 0; char username[USERNAME_SIZE]; char password[PASSWORD_SIZE];
while (isValidUser == 0) {
if (getNextMessage(socket, username, USERNAME_SIZE) > 0) {
if (getNextMessage(socket, password, PASSWORD_SIZE) > 0) {
The validateUser method will continuously check for a valid username and password without any restriction on the number of authentication attempts made. The method should limit the number of authentication attempts made to prevent brute force attacks as in the following example code.
(good code)
Example Language: C
int validateUser(char *host, int port) {
...
int count = 0; while ((isValidUser == 0) && (count < MAX_ATTEMPTS)) {
if (getNextMessage(socket, username, USERNAME_SIZE) > 0) {
if (getNextMessage(socket, password, PASSWORD_SIZE) > 0) {
Consider this example from a
real-world attack against the iPhone
[REF-1218]. An attacker can use brute force
methods; each time there is a failed guess, the
attacker quickly cuts the power before the failed
entry is recorded, effectively bypassing the
intended limit on the number of failed
authentication attempts. Note that this attack
requires removal of the cell phone battery and
connecting directly to the phone's power source,
and the brute force attack is still
time-consuming.
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.
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.
View - a subset of CWE entries that provides a way of examining CWE content. The two main view structures are Slices (flat lists) and Graphs (containing relationships between entries).
(this CWE ID may be used to map to real-world vulnerabilities)
Reason
Acceptable-Use
Rationale
This CWE entry is at the Base 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.
Taxonomy
Mappings
Mapped Taxonomy Name
Node ID
Fit
Mapped Node Name
PLOVER
AUTHENT.MULTFAIL
Multiple Failed Authentication Attempts not Prevented
Description
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.
