Well it is for me, and I guess anyone who consider themselves a career hacker, or at least has a serious interest..
As a few good trojans are open source (Back Orifice?), you can just mess around with them for a while until you reach the point they are no longer detected by any of the major anti-virus suites, then bind then to a file and off you go, instant access.
I remember once, someone actually believed I’d sent them a notepad.exe upgrade version…oh well, if only everyone was that stupid it would make our jobs so much easier.
Anyone back to the point, it seems customized trojans and malware is being created for specific attacks.
Anti-virus companies employee legions of researchers, honey pots, and customers to find viruses as soon as they appear in the wild. It takes on average about six hours to find, classify, and push out a new definition to your desktop. The Achilles heel of the whole industry is that these research techniques can do nothing to protect you against a custom virus or Trojan.
Custom malware is easy to create. Take the source code of an existing Trojan or virus, and modify it so that existing anti-virus and anti-spyware programs do not recognize it. And even if you or your IT department finds the Trojan, it does no good to report it, because it is not “in the wild.” So the developer of the custom Trojan can reuse his wares against other targets.
Sadly as always the AV industry is way behind, your anti-virus software only works if it has the correct definition, heuristics in the AV field are still very weak.
Anti-virus software is still reactive, not pro-active.
The infamous Trojan developed by Michael Haephrati and used to steal competitive information from dozens of companies in Israel was a custom Trojan. Now China is engaging in industrial-scale fishing expeditions against U.K. businesses and government agencies using a two-pronged attack.
The routine goes like this: First, a custom virus is sent in to harvest email addresses. It stays only within the target domain. Then, emails are sent to those addresses containing the custom Trojan. The reply-to addresses all appear to be within the same organization, making them more likely to be opened. Would you not open an email from your boss that said “Annual Appraisal Attached, Open Immediately”?
Social engineering combined with a custom trojan and some neat code, blended threats are always the most effective.
Again things like this can be stopped with education, it’s very hard to protect against such things with currect technology.
Host based intrusion detection can go a little way to helping..
Source: Dark Reading