Try Common(default) Usernames and Passwords
Attack Pattern ID: 70 (Detailed Attack Pattern Completeness: Complete)Typical Severity: HighStatus: Draft
+ Description


An attacker may try certain common (default) usernames and passwords to gain access into the system and perform unauthorized actions. An attacker may try an intelligent brute force using known vendor default credentials as well as a dictionary of common usernames and passwords.

Many vendor products come preconfigured with default (and thus well known) usernames and passwords that should be deleted prior to usage in a production environment. It is a common mistake to forget to remove these default login credentials. Another problem is that users would pick very simple (common) passwords (e.g. "secret" or "password") that make it easier for the attacker to gain access to the system compared to using a brute force attack or even a dictionary attack using a full dictionary.

+ Attack Prerequisites

The system uses one factor password based authentication.

+ Typical Likelihood of Exploit

Likelihood: Medium

+ Methods of Attack
  • Brute Force
+ Examples-Instances


User Bob sets his password to "123". If the system does not have password strength enforcement against a sound password policy, this password may be admitted. A simple numeric sequence like this is one of the most common passwords and is easily guessable by an attacker.


Cisco 2700 Series Wireless Location Appliances (version and earlier) have a default administrator username "root" with a password "password". This allows remote attackers to easily obtain administrative privileges.

Related Vulnerabilities


+ Attacker Skills or Knowledge Required

Skill or Knowledge Level: Low

An attacker just needs to gain access to common default usernames/passwords specific to the technologies used by the system. Additionally, a brute force attack leveraging common passwords can be easily realized if the user name is known.

+ Resources Required

Technology or vendor specific list of default usernames and passwords.

+ Probing Techniques

Try to determine what products are used in the implementation of the system. Determine if there are any default accounts associated with those products.

+ Indicators-Warnings of Attack

Many incorrect login attempts are detected by the system.

+ Obfuscation Techniques

Try to spoof IP addresses so that it does not look like the incorrect log in attempts are coming from the same computer.

+ Solutions and Mitigations

Delete all default account credentials that may be put in by the product vendor.

Implement a password throttling mechanism. This mechanism should take into account both the IP address and the log in name of the user.

Put together a strong password policy and make sure that all user created passwords comply with it. Alternatively automatically generate strong passwords for users.

Passwords need to be recycled to prevent aging, that is every once in a while a new password must be chosen.

+ Attack Motivation-Consequences
  • Privilege Escalation
+ Related Weaknesses
CWE-IDWeakness NameWeakness Relationship Type
521Weak Password RequirementsTargeted
262Not Using Password AgingTargeted
263Password Aging with Long ExpirationTargeted
798Use of Hard-coded CredentialsTargeted
693Protection Mechanism FailureTargeted
+ Related Attack Patterns
NatureTypeIDNameDescriptionView(s) this relationship pertains toView\(s\)
ChildOfAttack PatternAttack Pattern49Password Brute Forcing 
Mechanism of Attack (primary)1000
+ Related Security Principles
  • Failing Securely

+ Purposes
  • Penetration
+ CIA Impact
Confidentiality Impact: HighIntegrity Impact: HighAvailability Impact: Medium
+ Technical Context
Architectural Paradigms
+ Content History
Eugene LebanidzeCigital, Inc2007-02-26
Sean BarnumCigital, Inc2007-03-01Review and revision of content