The very first entry I posted at Krebs on Security, Virus Scanners for Virus Authors, introduced readers to two services that let virus writers upload their creations to see how well they are detected by numerous commercial anti-virus scanners. In this follow-up post, I take you inside of a pair of similar services that allow customers to periodically scan a malware sample and receive alerts via instant message or e-mail when a new anti-virus product begins to detect the submission as malicious.

While there are free services like VirusTotal and Jotti that will let visitors upload a suspicious file and scan it against dozens of commercial anti-virus tools, the reports produced by the scans are shared with all of the participating anti-virus makers so that those vendors can incorporate detection for newly discovered malware into their products. While virus writers probably would love to use such services to fine-tune the stealth of their malware, they may not want their unique malware samples broadly shared among the anti-virus community before the malware has even had a chance to infect PCs.

So it’s not hard to see why some malware authors and purveyors choose to avoid these free services in favor of subscription products that scan submitted files with multiple anti-virus engines, yet prevent those results from being shared with the anti-virus vendors. Such is the business model behind scan4you.biz, a service that charges 15 cents for each file checked. Scan4you will scan your malware against 30 anti-virus products, but promises it will bar those products from snarfing up a copy of the malware:

“This service is about to help you in anonymous check of different anti-virus system. This check will be made by numbers of anti-virus system and no reports will be send to developers of this anti-virus system. You can be fully sure that your files will not be send to anti-virus databases. All reporting system in our version of anti-virus engines was disabled MicrosoftSpyNet, ESET ThreatSense.Net Early Warning System etc.”

For 15 cents, you can scan your file to see if any potential victim’s anti-virus program will detect it. Or maybe you’re more interested in seeing how well your drive-by download site is flagged by anti-virus products as malicious? Perhaps you want to see whether your site is listed on any of the major spam and anti-malware blacklists? All these checks can be had for $0.15 each.

So your malware is invisible by to all anti-virus products? Yay for you, but it won’t stay that way: Sooner or later, the malware author is going to need to tweak his creation or replace it with a newer version, or risk having the invader detected and killed by anti-virus software on the victim’s PC. Probably the most innovative feature of scan4you.biz is a service that lets you choose the interval time to have your file re-scanned, and then receive alerts whenever an anti-virus product starts shipping detection for your malware. Customers can select anywhere from a 1-24 hour rescan interval, and receive update alerts via e-mail, ICQ, Gmail chat, or Jabber (see screen shot above).

Another service, avcheck.ru, does essentially the same thing — allowing users to scan their creations and receive periodic updates about future detection — but with fewer anti-virus products and fewer instant alert options.

I have often recommended file-scanning services like VirusTotal and Jotti, which allow visitors to upload a suspicious file and scan it against dozens of commercial anti-virus tools. If a scan generates any virus alerts or red flags, the report produced by the scan is shared with all of the participating anti-virus makers so that those vendors can incorporate detection for the newly discovered malware into their products.

That pooling of intelligence on new threats also serves to make the free scanning services less attractive to virus authors, who would almost certainly like nothing more than to freely and simultaneously test the stealth of their new creations across a wide range of security software. Still, there is nothing to stop an enterprising hacker from purchasing a license for each of the anti-virus tools on the market and selling access to a separate scanning service that appeals to the virus-writing community.

Enter upstart file-scanning services like av-check.com and virtest.com, which bank on the guarantee that they won’t share your results with the anti-virus community.

For $1 per file scanned (or a $40 monthly membership) av-check.com will see if your file is detected by any of 22 anti-virus products, including AVAST, AVG, Avira, BitDefender, NOD32, F-Secure, Kaspersky, McAfee, Panda, Sophos, Symantec, and Trend Micro. “Each of them is setten [sic] up on max heuristic check level,” av-check promises. “We guarantee that we don’t save your uploaded files and they are deleted immediately after the check. Also , we don’t resend your uploaded files to the 3rd person. Files are being checked only locally (without checking/using on other servers.” In other words: There is no danger that the results of these scans will somehow leak out to the anti-virus vendors.

The service claims that it will soon be rolling out advanced features, such as testing malware against anti-spyware and firewall programs, as well as a test to see whether the malware functions in a virtual machine, such as VMWare or VirtualBox. For safety and efficiency’s sake, security researchers often poke and prod new malware samples in a virtual environment. As a result many new families of malware are designed to shut down or destroy themselves if they detect they are being run inside of a virtual machine.

Virtest checks malware suspicious files against a similar albeit slightly different set of anti-virus programs, also promising not to let submitted files get back to the anti-virus vendors: “Your soft isn’t ever sent anywhere and the files being checked will never appear in the fresh AV signature bases after scanning,” the site pledges. “On purpose in all AV-products are turned off all possible methods and initiatives of exchange of files’ info with the AV-divisions.”

The proprietors of this service don’t even try to hide the fact that they have built it for malware writers. Among the chief distinguishing features of virtest.com is the ability for malware authors to test “exploit packs,” pre-packaged kits that — when stitched into a malicious or hacked Web site — serve the visitor’s browser with a kitchen sink full of code designed to install software via one of several known security holes. Many anti-virus programs now also scan Web pages for malicious content, and this service’s “exploits pack check” will tell malware authors whether their exploit sites are triggering virus alerts across a range of widely-used anti-virus software.

But don’t count on paying for these services via American Express: Both sites only accept payment via virtual currencies such as Webmoney and Fethard, services that appear to be popular with the online shadow economy.