CVE-2021-23146 - Incorrect Comparison

Severity

75%

Complexity

39%

Confidentiality

60%

An Incomplete Comparison with Missing Factors vulnerability in the Gallagher Controller allows an attacker to bypass PIV verification. This issue affects: Gallagher Command Centre 8.40 versions prior to 8.40.1888 (MR3); 8.30 versions prior to 8.30.1454 (MR3); 8.20 versions prior to 8.20.1291 (MR5); 8.10 versions prior to 8.10.1284 (MR7); version 8.00 and prior versions.

CVSS 3.1 Base Score 7.5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N).

CVSS 2.0 Base Score 5. CVSS Attack Vector: network. CVSS Attack Complexity: low. CVSS Vector: (AV:N/AC:L/Au:N/C:N/I:P/A:N).

Demo Examples

Incorrect Comparison

CWE-697

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.


               
}
}
return (this.make.equals(t.getMake()) && this.model.equals(t.getModel()));

Here, the equals() method only checks the make and model of the Truck objects, but the year of manufacture is not included.

Incorrect Comparison

CWE-697

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.


               
}/* Ignore CWE-259 (hard-coded password) and CWE-309 (use of password system for authentication) for this example. */
}
return(AUTH_FAIL);
return(AUTH_SUCCESS);
return(AUTH_FAIL);
}
ExitError("Usage: Provide a username and password");
DoAuthenticatedTask(argv[1]);
ExitError("Authentication failed");

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:


               
pass

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.

Overview

First reported 2 weeks ago

2021-11-18 18:15:00

Last updated 1 week ago

2021-11-24 02:22:00

Affected Software

Gallagher Command Centre

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