Most security professionals agree that we can’t effectively stop malware by blacklisting signatures, an approach used by most anti-malware applications. But what about other legacy anti-malware solutions such as behavior-based host-based intrusion detection systems (HIDS) or host-based intrusion prevention systems (HIPS)?
The promise of the HIDS/HIPS solution was big: By monitoring system behavior and network traffic, these solutions would be able to determine which behavior is normal and which may indicate an attack. However, it turns out that this approach is not so easy. Defining the policies and rules that determine which behavior is “normal” and which indicates an attack is a very difficult and time-consuming task that requires deep understanding and expertise. As a result, most of the HIDS/HIPS rules and policies are not deterministic enough, which results in many false-positive alerts. HIDS/HIPS administrators have problems keeping false-positives to a minimum. In come cases, false-positives have become so annoying that the alerts are ignored because they are triggered far too often. If the alerts are ignored, what’s the point in having them? Of course, this dramatically hinders security efforts, and security administrators should never let it get to this point.
To minimize false-positives, it is necessary to constantly tune HIDS/HIPS rules and policies. Every time a new application is installed, updated or patched, the HIDS/HIPS solution must be retuned. This creates a huge burden on the solution administrators, who need to understand each alteration when it is triggered. It also increases the total cost of solution ownership. The cost of professional resources required for initial setup, ongoing maintenance, tuning and administration of the solution and training and user support drives the solution costs very high.
False-positives are also very annoying to the end user. Most enterprise users are not security experts. They don’t understand — and often don’t care about — the security alerts that pop up on their screens. All they know is that these alerts are preventing them from doing their job. If this happens too often, users will demand that the solution is removed from their desktop, rendering it ineffective. Again, never let it get to this point.
Recommendations
Thankfully, we’ve come a long way since the days of HIDS and HIPS solutions. Trying to determine that an action is malicious only by examining host behavior has proven to be an ineffective method because it lacks the context of the operation. Only by understanding both the application operation and its context is it possible to accurately determine whether the operation is valid.
IBM Security provides a solution that is accurate, effective, transparent to the user and requires a minimal investment of IT resources, so customers really do get the best of both worlds.
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Director of Enterprise Security at Trusteer, an IBM Company