5.5 CVE-2020-1472

In this attack, some asset (information, functionality, identity, etc.) is protected by a finite secret value. The attacker attempts to gain access to this asset by using trial-and-error to exhaustively explore all the possible secret values in the hope of finding the secret (or a value that is functionally equivalent) that will unlock the asset. [Determine secret testing procedure] Determine how a potential guess of the secret may be tested. This may be accomplished by comparing some manipulation of the secret to a known value, use of the secret to manipulate some known set of data and determining if the result displays specific characteristics (for example, turning cryptotext into plaintext), or by submitting the secret to some external authority and having the external authority respond as to whether the value was the correct secret. Ideally, the attacker will want to determine the correctness of their guess independently since involvement of an external authority is usually slower and can provide an indication to the defender that a brute-force attack is being attempted. [Reduce search space] Find ways to reduce the secret space. The smaller the attacker can make the space they need to search for the secret value, the greater their chances for success. There are a great many ways in which the search space may be reduced. [Expand victory conditions] It is sometimes possible to expand victory conditions. For example, the attacker might not need to know the exact secret but simply needs a value that produces the same result using a one-way function. While doing this does not reduce the size of the search space, the presence of multiple victory conditions does reduce the likely amount of time that the attacker will need to explore the space before finding a workable value. [Gather information so attack can be performed independently.] If possible, gather the necessary information so a successful search can be determined without consultation of an external authority. This can be accomplished by capturing cryptotext (if the goal is decoding the text) or the encrypted password dictionary (if the goal is learning passwords).

An attacker obtains an authoritative or reputable signer's private signature key by exploiting a cryptographic weakness in the signature algorithm or pseudorandom number generation and then uses this key to forge signatures from the original signer to mislead a victim into performing actions that benefit the attacker.

This attack targets predictable session ID in order to gain privileges. The attacker can predict the session ID used during a transaction to perform spoofing and session hijacking. [Find Session IDs] The attacker interacts with the target host and finds that session IDs are used to authenticate users. [Characterize IDs] The attacker studies the characteristics of the session ID (size, format, etc.). As a results the attacker finds that legitimate session IDs are predictable. [Match issued IDs] The attacker brute forces different values of session ID and manages to predict a valid session ID. [Use matched Session ID] The attacker uses the falsified session ID to access the target system.