Hackers may have created a back door onto your network.
Some hacks require the addition of new code, followed by a reboot to load it.
Sometimes, hackers can only cover their tracks by deleting portions of files. Gaps, then, become the telltale tracks. Each company is different, but these critical logs are usually spare because only a few people have access. If a hacker is impersonating a ''sys-op,'' you'll see it here. The McGraw-Hill Companies Inc. All rights reserved.