CWE-697: Incorrect Comparison | Glexia

Causes

• Consider an application in which Truck objects are defined to be the same if they have the same make, the same model, and were manufactured in the same year. Here, the equals() method only checks the make and model of the Truck objects, but the year of manufacture is not included.
• This example defines a fixed username and password. The AuthenticateUser() function is intended to accept a username and a password from an untrusted user, and check to ensure that it matches the username and password. If the username and password match, AuthenticateUser() is intended to indicate that authentication succeeded. In AuthenticateUser(), the strncmp() call uses the string length of an attacker-provided inPass parameter in order to determine how many characters to check in the password. So, if the attacker only provides a password of length 1, the check will only examine the first byte of the application's password before determining success.,As a result, this partial comparison leads to improper authentication (CWE-287).,Any of these passwords would still cause authentication to succeed for the "admin" user:,This significantly reduces the search space for an attacker, making brute force attacks more feasible.,The same problem also applies to the username, so values such as "a" and "adm" will succeed for the username.,While this demonstrative example may not seem realistic, see the Observed Examples for CVE entries that effectively reflect this same weakness.

Remediation

• Use safe APIs
• Centralize the control
• Add regression tests
• Review logs and telemetry for attempted abuse

Detection

• 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.)

Related CWEs

• CWE-1023: Incomplete Comparison with Missing Factors
• CWE-1024: Comparison of Incompatible Types
• CWE-1025: Comparison Using Wrong Factors
• CWE-1039: Inadequate Detection or Handling of Adversarial Input Perturbations in Automated Recognition Mechanism
• CWE-1077: Floating Point Comparison with Incorrect Operator
• CWE-1254: Incorrect Comparison Logic Granularity
• CWE-183: Permissive List of Allowed Inputs
• CWE-185: Incorrect Regular Expression
• CWE-481: Assigning instead of Comparing
• CWE-581: Object Model Violation: Just One of Equals and Hashcode Defined

Related CVEs

Related CVE mappings appear after CVE records are cross-indexed.

ATT&CK Relevance

ATT&CK relevance is shown only when reviewed or responsibly inferred.