CWE-307: Improper Restriction of Excessive Authentication Attempts

Detection Methods

Method

Dynamic Analysis with Automated Results Interpretation

Description

According to SOAR [REF-1479], the following detection techniques may be useful: Highly cost effective: Web Application Scanner Web Services Scanner Database Scanners Cost effective for partial coverage: Host-based Vulnerability Scanners - Examine configuration for flaws, verifying that audit mechanisms work, ensure host configuration meets certain predefined criteria

Effectiveness

High

Method

Dynamic Analysis with Manual Results Interpretation

Description

According to SOAR [REF-1479], the following detection techniques may be useful: Highly cost effective: Fuzz Tester Framework-based Fuzzer Cost effective for partial coverage: Forced Path Execution

Effectiveness

High

Method

Manual Static Analysis - Source Code

Description

According to SOAR [REF-1479], the following detection techniques may be useful: Highly cost effective: Focused Manual Spotcheck - Focused manual analysis of source Manual Source Code Review (not inspections)

Effectiveness

High

Method

Automated Static Analysis - Source Code

Description

According to SOAR [REF-1479], the following detection techniques may be useful: Cost effective for partial coverage: Source code Weakness Analyzer Context-configured Source Code Weakness Analyzer

Method

Automated Static Analysis

Description

According to SOAR [REF-1479], the following detection techniques may be useful: Cost effective for partial coverage: Configuration Checker

Method

Architecture or Design Review

Description

According to SOAR [REF-1479], the following detection techniques may be useful: Highly cost effective: Formal Methods / Correct-By-Construction Cost effective for partial coverage: Inspection (IEEE 1028 standard) (can apply to requirements, design, source code, etc.)

Effectiveness

High

Code Examples & CVEs

Demonstrative Examples

The following code, extracted from a servlet's doPost() method, performs an authentication lookup every time the servlet is invoked.

However, the software makes no attempt to restrict excessive authentication attempts.

BadJava

String username = request.getParameter("username");String password = request.getParameter("password");                      int authResult = authenticateUser(username, password);

This code attempts to limit the number of login attempts by causing the process to sleep before completing the authentication.

However, there is no limit on parallel connections, so this does not increase the amount of time an attacker needs to complete an attack.

BadPHP

$username = $_POST['username'];$password = $_POST['password'];sleep(2000);$isAuthenticated = authenticateUser($username, $password);

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.

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.

BadC

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) {isValidUser = AuthenticateUser(username, password);}}                            }return(SUCCESS);                      }

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.

GoodC

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) {isValidUser = AuthenticateUser(username, password);}}count++;                            }if (isValidUser) {return(SUCCESS);}else {return(FAIL);}                      }

Observed CVE Examples (7)

CVE-2019-0039

the REST API for a network OS has a high limit for number of connections, allowing brute force password guessing

View Details

CVE-1999-1152