Vulnerabilities > CVE-2018-17888 - Use of Insufficiently Random Values vulnerability in Nuuo CMS 3.1

047910
CVSS 7.5 - HIGH
Attack vector
NETWORK
Attack complexity
LOW
Privileges required
NONE
Confidentiality impact
PARTIAL
Integrity impact
PARTIAL
Availability impact
PARTIAL
network
low complexity
nuuo
CWE-330
metasploit

Summary

NUUO CMS all versions 3.1 and prior, The application uses a session identification mechanism that could allow attackers to obtain the active session ID, which could allow arbitrary remote code execution.

Vulnerable Configurations

Part Description Count
Application
Nuuo
1

Common Weakness Enumeration (CWE)

Common Attack Pattern Enumeration and Classification (CAPEC)

  • Brute Force
    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. Examples of secrets can include, but are not limited to, passwords, encryption keys, database lookup keys, and initial values to one-way functions. The key factor in this attack is the attackers' ability to explore the possible secret space rapidly. This, in turn, is a function of the size of the secret space and the computational power the attacker is able to bring to bear on the problem. If the attacker has modest resources and the secret space is large, the challenge facing the attacker is intractable. While the defender cannot control the resources available to an attacker, they can control the size of the secret space. Creating a large secret space involves selecting one's secret from as large a field of equally likely alternative secrets as possible and ensuring that an attacker is unable to reduce the size of this field using available clues or cryptanalysis. Doing this is more difficult than it sounds since elimination of patterns (which, in turn, would provide an attacker clues that would help them reduce the space of potential secrets) is difficult to do using deterministic machines, such as computers. Assuming a finite secret space, a brute force attack will eventually succeed. The defender must rely on making sure that the time and resources necessary to do so will exceed the value of the information. For example, a secret space that will likely take hundreds of years to explore is likely safe from raw-brute force attacks.
  • Signature Spoofing by Key Recreation
    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.
  • Session Credential Falsification through Prediction
    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.

Metasploit

descriptionNuuo Central Management Server below version 2.4 has a flaw where it sends the heap address of the user object instead of a real session number when a user logs in. This can be used to reduce the keyspace for the session number from 10 million to 1.2 million, and with a bit of analysis it can be guessed in less than 500k tries. This module does exactly that - it uses a computed occurence table to try the most common combinations up to 1.2 million to try to guess a valid user session. This session number can then be used to achieve code execution or download files - see the other Nuuo CMS auxiliary and exploit modules. Note that for this to work a user has to be logged into the system.
idMSF:AUXILIARY/GATHER/NUUO_CMS_BRUTEFORCE
last seen2020-06-12
modified2019-04-24
published2019-01-21
references
reporterRapid7
sourcehttps://github.com/rapid7/metasploit-framework/blob/master//modules/auxiliary/gather/nuuo_cms_bruteforce.rb
titleNuuo Central Management Server User Session Token Bruteforce