The cyber thieves who hit Target Corp. took advantage of a widespread and often overlooked weakness in corporate information security: third-party computer connections that can create a virtual back door to customer information.
Digital links with suppliers, contractors or consultants are essential to run a complex business in the Internet age. Yet, even as companies spend millions to bolster the security of their networks, the access vendors are given doesn't get nearly enough attention, several information security professionals say.
Hackers gained access to Target's computer systems through the stolen credentials of a heating and refrigeration contractor. Once inside, the thieves were able to move around and ultimately stole payment card data card or personal information of up to 110 million Target customers.
Given that the typical Fortune 1000 company likely has thousands of active suppliers, hackers have plenty of ways to infiltrate, said Jeff Hall, a security consultant in the Twin Cities for Overland, Kan.-based Fish Net Security.
"I've hacked companies through their elevator contractors," Hall said.
Most companies don't view third party vendors as a major security threat, said David Kennedy, founder of the security firm TrustedSec. in Strongsville, Ohio. Vendor management, as he describes it, is "extremely loose."
Security pros consider the supply chain a critical security risk -- ranking with the classic employee insider attack and the traditional hack, where an outsider ferrets a hole in a company's firewall.
"In the modern world, business-to-business connections are the weakest link," said Brian Isle, founder of the Minneapolis-based cyber security firm Adventium Labs. "The first thing an attacker will do is look at who you do business with."
One Door Opens Many
Once a skilled hacker gains entry into a company's network, they frequently can move around even if there's segmentation such as firewalls with rules that restrict network traffic, said TrustedSec's Kennedy. "The rest of it is basically wide open," he said.
Investigations into Target's hack, one of the largest recorded data breaches in U.S. history, continue. It's not yet clear how cyberthieves stole the network access credentials from Fazio Mechanical Services Inc., a heating and refrigeration company in Sharpsburg, Penn., first identified by investigative security blogger Brian Krebs at KrebsonSecurity as the point of entry.
It's also unclear how they moved from vendor access to the point of sale systems in Target's stores. That's where malware was discovered that allowed hackers to collect unencrypted card data.
Isle, Kennedy and others encourage clients to run penetration tests, sometimes called Red Teaming, in which expert crews stage hack attacks to sleuth out vendor vulnerabilities to fix so the bad guys can't get in. (continued...)
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