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We've Been Hacked... or Have We?
hidden_fire asks: "I recently got a job as a Web Programmer at a web company that hosts many sites. The company had many badly firewalled Windows and Linux servers without any security patches, and a shared administrator password. I warned them that they needed to improve their security, but was ignored until a hacker kindly emailed them proof that their credit-card server was compromised, and the Sasser Worm took us offline. Now, I've been allowed to rebuild the compromised box and tighten our firewalling, but our other servers show many signs of possibly being compromised including unexplained outgoing traffic, a Linux kernel lockup, strange ports being open, and performance issues. I think we are possibly providing hosting for undetectable spammers but the boss thinks I'm paranoid, and says that I need to be working on paying work, not security. Has anybody else been in this situation? How can I detect these guys if their tools don't show in virus scans?"
Windows: use Moosoft's The Cleaner (http://www.moosoft.com/products/cleaner/download/ ) - it can detect trojans and things that virus scanners don't pick up...
Linux: nmap the box from a trusted PC on the same network, and then build a copy of netstat on the trusted PC for the server in question... copy the binary over, and run "netstat -pultw" as root... it'll list all ports that are listening for connections, and, the processes that are opening them (by PID, and usually by name). The reason for the clean copy is that a lot of root kits replace netstat on infection...
Hope this helps...
-PhaseBurn Welcome to Linux country. On quiet nights, you can hear windows reboot.
There are stories just now breaking into the general consciousness of IIS servers that have been compromised for months and feeding executable code tacked on the end of http calls to IE and spreading malicious code and feeding something (reports and opinions vary) to servers in Russia (also with varying opinions as to the owners - organized crime seems to be the evil de jour).
These compromised IIS servers often have the server attached to the explorer.exe process and are therefore not detectable by virus scans. Using netstat or filemon you can find the open ports. The only solution is a bare-metal rebuild.
Have fun if that is what you are dealing with.
As an aside, if this company is unconcerned about the compromise of credit card information you might want to find a new place to hang your hat. The civil and criminal liabilities are pretty steep for the compromise of financial transaction information (if you are in the U.S.) and they extend to individuals inside the company, not just the board and officers.