CVE-2018-15807 - Use of Insufficiently Random Values

Severity

46%

Complexity

39%

Confidentiality

106%

POSIM EVO 15.13 for Windows includes an "Emergency Override" administrative account that may be accessed through POSIM's "override" feature. This Override prompt expects a code that is computed locally using a deterministic algorithm. This code may be generated by an attacker and used to bypass any POSIM EVO login prompt.

POSIM EVO 15.13 for Windows includes an "Emergency Override" administrative account that may be accessed through POSIM's "override" feature. This Override prompt expects a code that is computed locally using a deterministic algorithm. This code may be generated by an attacker and used to bypass any POSIM EVO login prompt.

CVSS 3.0 Base Score 7.8. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).

CVSS 2.0 Base Score 4.6. CVSS Attack Vector: local. CVSS Attack Complexity: low. CVSS Vector: (AV:L/AC:L/Au:N/C:P/I:P/A:P).

Demo Examples

Use of Insufficiently Random Values

CWE-330

This code generates a unique random identifier for a user's session.


               
}
return rand();

Because the seed for the PRNG is always the user's ID, the session ID will always be the same. An attacker could thus predict any user's session ID and potentially hijack the session.

This example also exhibits a Small Seed Space (CWE-339).

Use of Insufficiently Random Values

CWE-330

The following code uses a statistical PRNG to create a URL for a receipt that remains active for some period of time after a purchase.


               
}
return(baseUrl + ranGen.nextInt(400000000) + ".html");

This code uses the Random.nextInt() function to generate "unique" identifiers for the receipt pages it generates. Because Random.nextInt() is a statistical PRNG, it is easy for an attacker to guess the strings it generates. Although the underlying design of the receipt system is also faulty, it would be more secure if it used a random number generator that did not produce predictable receipt identifiers, such as a cryptographic PRNG.

Overview

First reported 6 years ago

2018-08-23 20:29:00

Last updated 5 years ago

2019-10-03 00:03:00

Affected Software

Posim Evo 15.13 for Windows

15.13
windows

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