Hacking

The Simplest Way to Get a Password

The Simplest Way to Get a Password

Many hacking attempts start with getting a password to a target system. Passwords are the key piece of information needed to access a system, and users often select passwords that are easy to guess. Many reuse passwords or choose one that’s simple—such as a pet’s name—to help them  remember it. Because of this human factor, most password guessing is successful if some information is known about the target. Information gathering and reconnaissance can help give away information that will help a hacker guess a user’s password. Once a password is guessed or cracked, it can be the launching point for escalating privileges, executing applications, hiding files, and covering tracks. If guessing a password fails, then passwords may be cracked manually or with automated tools such as a dictionary or brute-force method, each of which are covered later in this chapter.

Types of Passwords

Several types of passwords are used to provide access to systems. The characters that form
a password can fall into any of these categories:
  •  Only letters
  •  Only numbers
  •  Only special characters
Another passive online attack is known as man-in-the-middle (MITM). In a MITM attack, the hacker intercepts the authentication request and forwards it to the server. By inserting a sniffer between the client and the server, the hacker is able to sniff both connections and capture passwords in the process. A replay attack is also a passive online attack; it occurs when the hacker intercepts the password en route to the authentication server and then captures and resends the authentication packets for later authentication. In this manner, the hacker doesn’t have to break the password or learn the password through MITM but rather captures the password and reuses the password-authentication packets later to authenticate as the client.
Active Online Attacks
The easiest way to gain administrator-level access to a system is to guess a simple password assuming the administrator used a simple password. Password guessing is an active online attack. It relies on the human factor involved in password creation and only works on weak passwords.I Enumeration phase of system hacking, you learned the vulnerability of NetBIOS enumeration and null sessions. Assuming that the NetBIOS TCP 139 port is open, the most effective method of breaking into a Windows NT or Windows 2000 system is password guessing. This is done by attempting to connect to an enumerated share (IPC$ or C$) and trying a username and password combination. The most commonly used Administrator account and password combinations are words like Admin,
Administrator, Sysadmin, or Password, or a null password.
A hacker may first try to connect to a default Admin$, C$, or C:\Windows share. To connect to the hidden C: drive share, for example, type the following command in the Run field (Start > Run): \\ip_address\c$Automated programs can quickly generate dictionary files, word lists, or every possible combination of letters, numbers, and special characters and then attempt to log on using those credentials. Most systems prevent this type of attack by setting a maximum number of login attempts on a system before the account is locked. In the following sections, we’ll discuss how hackers can perform automated password guessing more closely, as well as countermeasures to such attacks.
Another example of how the FOR command can be used by an attacker is to wipe the contents of the hard disk with zeros using the command syntax ((i=0; i<11; i++)); do dd if=/dev/random of=/dev/hda && dd if=/ dev/zero of=dev/hda done. The wipe command could also be used to perform the wiping of data from the hard disk using the command $ wipe -fik /dev/hda1.
Harinder
the authorHarinder
blacklisthackers.com is created and owned by Harinder(Aarav).Aarav is a technology Blogger from India(Dehradun). He’s Quiet type and Creative Guy who enjoys creating and exploring new trends on the WEB. Currently pursuing B.tech from DIT University.

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