The product compares two entities in a security-relevant context, but the comparison is incorrect, which may lead to resultant weaknesses.
This Pillar covers several possibilities: the comparison checks one factor incorrectly; the comparison should consider multiple factors, but it does not check at least one of those factors at all; the comparison checks the wrong factor.
Threat Mapped score: 0.0
Industry: Finiancial
Threat priority: Unclassified
CVE: CVE-2021-3116
Chain: Python-based HTTP Proxy server uses the wrong boolean operators (CWE-480) causing an incorrect comparison (CWE-697) that identifies an authN failure if all three conditions are met instead of only one, allowing bypass of the proxy authentication (CWE-1390)
CVE: CVE-2020-15811
Chain: Proxy uses a substring search instead of parsing the Transfer-Encoding header (CWE-697), allowing request splitting (CWE-113) and cache poisoning
CVE: CVE-2016-10003
Proxy performs incorrect comparison of request headers, leading to infoleak
| Phase | Note |
|---|---|
| Implementation | N/A |
Intro: 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.
Body: Here, the equals() method only checks the make and model of the Truck objects, but the year of manufacture is not included.
public class Truck { private String make; private String model; private int year; public boolean equals(Object o) { if (o == null) return false; if (o == this) return true; if (!(o instanceof Truck)) return false; Truck t = (Truck) o; return (this.make.equals(t.getMake()) && this.model.equals(t.getModel())); } }Intro: 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.
Body: 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.
/* Ignore CWE-259 (hard-coded password) and CWE-309 (use of password system for authentication) for this example. */ char *username = "admin"; char *pass = "password"; int AuthenticateUser(char *inUser, char *inPass) { if (strncmp(username, inUser, strlen(inUser))) { logEvent("Auth failure of username using strlen of inUser"); return(AUTH_FAIL); } if (! strncmp(pass, inPass, strlen(inPass))) { logEvent("Auth success of password using strlen of inUser"); return(AUTH_SUCCESS); } else { logEvent("Auth fail of password using sizeof"); return(AUTH_FAIL); } } int main (int argc, char **argv) { int authResult; if (argc < 3) { ExitError("Usage: Provide a username and password"); } authResult = AuthenticateUser(argv[1], argv[2]); if (authResult == AUTH_SUCCESS) { DoAuthenticatedTask(argv[1]); } else { ExitError("Authentication failed"); } }