The cyberthieves 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 Park, Kan.-based FishNet 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 cybersecurity 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 cyber thieves 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.
Until now, however, corporate information security efforts have focused more on the insider attack and the traditional outsider hacker, said Greg Brown, chief technology officer of Cloud and Internet of Things at McAfee, a leading computer security company based in Santa Clara, Calif. They generally haven't been applied to the chain of third parties companies do business with, he said.
Fazio President Ross Fazio issued a statement last Thursday saying his company, too, was a "victim of a sophisticated cyberattack operation."
"Fazio Mechanical does not perform remote monitoring of or control of heating, cooling and refrigeration systems for Target," Fazio said.
Citing the ongoing investigations, Target would not discuss its protocol for granting computer access to vendors or what firewalls it built to keep consumers' credit card and personal data secure.
Target Chief Financial Officer John Mulligan testified in Congressional hearings last week that Target has invested "hundreds of millions of dollars" over the past several years in information security, including segmentation, malware detection, intrusion detection and prevention, and data loss prevention.
Not enough
Still, it wasn't enough.
Point of sale systems are particularly vulnerable, TrustedSec's Kennedy said, because companies typically don't want to make changes to them, such as adding security enhancements. After all, taking systems down for any length of time can directly affect sales.
"These POS networks are usually Swiss cheese," Kennedy said. "They're just terrible."
McAfee's Brown said he doesn't think the industry's safe-practice guidelines, called the Payment Card Industry Data Security Standards and referred to as PCI, do much to address the data vulnerabilities in a company's supply chain.
"It doesn't explicitly call out third-party relationships like we're talking about," Brown said.
Bob Russo, general manager of the PCI Security Standards Council, said the guidelines require merchants to use what's called "two-factor authentication" for all third parties using remote network access to a company's network, if the access could lead to the area where cardholder data exists. Such login verification requires two out of three things, he said: something you have (such as a smart card), something you know (a password) or something you are (fingerprint or eye scan, for instance.)
Vendors need watching
The PCI standards don't specifically address all vendor connections or require formal vendor risk assessments, Russo said in a written response to questions, but vendor connections should be part of the annual risk assessment companies are required to conduct.
PCI standards don't require card encryption at the point of sale, which means there's a millisecond after a swipe when information is out in the open, unencrypted.
"The key message here is to understand the security controls your vendors and business partners have in place when allowing them access to your network," said Chad Boeckmann CEO of Secure Digital Solutions in Minneapolis. "I know many big companies conduct those exercises, but sometimes those exercises aren't conducted frequently enough or they're not conducted thoroughly enough."
Cybercrime cost $113 billion in 2013 and exposed 435 million people to information theft, Frank Rosch of the computer security software firm Symantec told the Senate Judiciary Committee in a hearing last week. Targeted attacks on computer systems such as Target's are expanding, he added.
Isle, at Adventium Labs, says a breach was probably inevitable given the Secret Service's description of the criminals as relentless, well-organized and sophisticated.
"With unlimited people, time and money, they will get in," said Isle. "Target may or may not have screwed up, but the people who came at them were good."
Jim Spencer • 202-383-6123
Jennifer Bjorhus 612-673-4683
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