How do hackers get into a computer system?
Hackers get into a computer system by exploiting a weakness or hole in the computer's operating system. Very often this activity begins by logging into the target system by means of a stolen userid and password of a legitimate user.
Computer operating systems are by nature complex entities; working to ensure that any potential weaknesses in the system are addressed is more than a full-time job. The administrators of the acpub system are vigilant in keeping up with documented system weaknesses and address them as soon as they are discovered.
Other systems on campus--departmental systems and those that individuals bring up themselves--are not necessarily as well-protected. When those running them are not up on the constantly-changing knowledge of security issues, these systems become vulnerable to intruders.
What exactly happens when someone hacks into a computer system?
The most common thing hackers do is collect userids and passwords, either those stored on disk, or as they travel across the network. These are valuable to them not only as a means of entering a system, but also to trade with other hackers.The most common method of operation for a hacker is the following:
- 1) Gain access to the system as a normal user. (This step is sort of optional, sometimes the hackers will jump straight to step 2)
- 2) Use the user access to gain access as the administrator (root user) of the computer.
- 3) Grab the password file
- 4) Start "sniffing" the network to find passwords
- 5) Clean up by deleting or changing logs that would show how they got in
- 6) Change system programs to help hide the fact that they are using your computer
- 7) Proceed with their other objectives: hacking new systems or starting a denial of service attack or starting up a new server (like IRC) on you computer, etc.