The sign outside the Target store is seen in Arvada, Colorado January 10, 2014. 
 
 WASHINGTON The FBI has warned U.S. retailers to prepare for more cyber attacks after discovering about 20 hacking cases in the past year that involved the same kind of malicious software used against Target Corp in the holiday shopping season. 
 
 The U.S. Federal Bureau of Investigation distributed a confidential, three-page report to retail companies last week describing the risks posed by "memory-parsing" malware that infects point-of-sale (POS) systems, which include cash registers and credit-card swiping machines found in store checkout aisles. 
 
 "We believe POS malware crime will continue to grow over the near term, despite law enforcement and security firms' actions to mitigate it," said the FBI report, seen by Reuters. 
 
 "The accessibility of the malware on underground forums, the affordability of the software and the huge potential profits to be made from retail POS systems in the United States make this type of financially motivated cyber crime attractive to a wide range of actors," the FBI said. 
 
 The report was dated January 17 and entitled "Recent Cyber Intrusion Events Directed Toward Retail Firms." A spokeswoman for the FBI confirmed the agency had issued the report as part of efforts to share information about threats with the private sector. 
 
 Retail, credit card and bank industry executives have become increasingly concerned about the security of payment card networks after Target, the No. 3 U.S. retailer, last month disclosed one of the biggest retail cyber attacks in history. 
 
 The attack ran undetected for 19 days during the busy holiday shopping season and resulted in the theft of about 40 million credit and debit card records. The personal information of 70 million customers was also compromised. 
 
 Luxury retail chain Neiman Marcus has said it too was the victim of a cyber attack, and sources have told Reuters that other retail chains have also been breached. Neiman Marcus said about 1.1 million customer cards were exposed by a data breach from July 16 to October 30 last year. 
 
 In all these attacks, cyber criminals used memory-parsing software, also known as a "RAM scraper." When a customer swipes a credit or debit card, the POS terminal grabs the transaction data from the magnetic stripe and transfers it to the retailer's payment processing provider. While the data is encrypted during the process, RAM scrapers extract the information while it is in the computer's live memory, where it very briefly appears in plain text. 
 
 RAM scraping technology has been around for a long time, but its use has increased in recent years. Developers of the malware have also enhanced its features to make it more difficult to be detected by anti-virus software deployed on POS systems running Windows software. 
 
 MALWARE ON SALE UNDERGROUND 
 
 The FBI said in its report that one variant of the malicious POS software, known as Alina, included an option that allowed remote upgrades, making it tougher for corporate security teams to identify and eradicate it. The report said at least one type of malware has been offered for sale for as much as $6,000 in a "well-known" underground forum. 
 
 "The high dollar value gained from some of these compromises can encourage intruders to develop high sophistication methodologies, as well as incorporate mechanisms for the actors to remain undetected," the report said. 
 
 Asked to comment on the FBI warning, the National Retail Federation industry trade group said retailers are alert to cyber risks. 
 
 "Retailers have been and remain vigilant in their efforts to provide the highest level of security for their data systems in order to protect against malicious and criminal acts," NRF Vice President Tom Litchford said in a statement. 
 
 "As the criminal investigation continues and more information becomes available, you can be sure that the retail industry will be responsive and engaged to ensure this particular cyber-attack does not happen again." 
 
 One cyber security consultant who has reviewed the FBI report, said the findings were troubling. 
 
 "Everybody we work with in the retail space is scared to death because they don't have a lot of defenses to prepare against these types of attacks," said the consultant, who is advising several retailers in current investigations. 
 
 "This is not just based on anybody saying 'This is going to happen.' This is based on statistical data that the FBI is seeing," said the consultant, who was not authorized to publicly comment on the details of the report. 
 
 Retailers need to move quickly to get better tools in their networks that can analyze traffic patterns on the fly and identify any unusual activity, said another expert in retail security, who has audited POS systems to find vulnerabilities that hackers can exploit. 
 
 The expert said it is more difficult for small-to-mid sized retailers to do this because they do not have as much money and expertise as major retailers. 
 
 The FBI report said the bulk of the POS malware cases that the agency has investigated involve small-to-mid sized local or regional businesses, whose estimated losses each range from tens of thousands of dollars to millions of dollars. 
 
 The United States Secret Service usually takes the lead in credit card breach investigations for the federal government, though the FBI sometimes opens its own cases or asked to assist. The Secret Service is leading the investigations into the breaches at Target and Neiman Marcus. 
 
 A spokesman for the Secret Service declined to comment on the FBI report to retailers. 
 
 (Reporting by Jim Finkle and Mark Hosenball; Editing by Tiffany Wu and Grant McCool) ||||| A 17-page report from a computer firm hired to look into the massive data breach at Target stores provides new insight into the holiday hacking that endangered data for more than 100 million customers. 
 
 The report, from computer firm iSight, was filed to the U.S. Secret Service and obtained by NBC News. It details the type of software used in the massive hack, how it was effective and mentions regions known to have the software coding prowess to pull off this kind of digital heist. 
 
 The report however does not draw conclusions on who is ultimately responsible for the attack that scooped up credit and debit card data for tens of millions of customers, citing an active U.S. government investigation. 
 
 The data breach was caused by a type of malware, similar to a computer virus, placed in a store's point-of-sale systems, it said. 
 
 "While some components of the breach operation were technically sophisticated, the operational sophistication of the compromise activity makes this case stand out," according to the iSight report. "The intrusion operators displayed innovation and a high degree of skill in orchestrating the various components of the activity." 
 
 The report details specific regions where software capabilities exist to create the malware. 
 
 "Memory scraping capabilities has been available in the Russian-language underground for some time," the report reads. "While Eastern Europe has been the focal point for POS malware development and use, cyber criminals in Brazil have used the technique since at least 2009. Globally, this trend will probably continue because malware offers important cost and risk advantages over hardware skimming techniques." 
 
 Here's how the malware works, according to the report: The insidious file triggers a "hook" and starts to suck up information on transactions in the memory of the cash register system or the server that controls it. Since the data on credit cards is encrypted, the system works by getting it in the authorization stage while it is in the memory of the POS system, unencrypted. 
 
 The tactic used during the Target holiday hackers is "new to eCrime," the report says, and "covertly subverts network controls and common forensic tactics to conceal all data transfers." 
 
 The report concludes that since this style of POS hacking can net big rewards for the cyber crooks with little risk, cardholders can expect more of this type of breach. 
 
 NBC News' Matthew DeLuca contributed to this report. 
 
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 Investigate this! Read and vote on readers' story tips and suggested topics for investigation or submit your own. Click here to read more about this tool. ||||| During an interview with CNBC, retailer's CEO defends four-day delay in notifying customers of security breach as necessary for the investigation and preparation for consumer reaction. 
 
 Hackers infected Target's point-of-sale terminals with malware to steal the payment card information from millions of customers, the retailer's chief executive has confirmed. 
 
 The security breach, which yielded the personal information of as many as 110 million customers, was first identified on December 15, four days before the breach was publicly revealed, CEO Gregg Steinhafel told CNBC during an interview. Target revealed Friday that the security breach it suffered between November 27 and December 15 was larger than originally believed, yielding the names, mailing addresses, phone numbers, and e-mail addresses for near three times its original estimate of 40 million customers. 
 
 "Sunday [December 15] was really Day 1. That was the day we confirmed we had an issue and so our number one priority was ... making our environment safe and secure," Steinhafel said in the interview. "By six o'clock at night, our environment was safe and secure. We eliminated the malware in the access point, we were very confident that coming into Monday guests could come to Target and shop with confidence and no risk." 
 
 Steinhafel defended the four-day delay in its notification process as necessary for investigators and consumer preparation. 
 
 "Day 2 was really about initiating the investigation work and the forensic work ... that has been ongoing. Day 3 was about preparation. We wanted to make sure our stores and our call centers could be as prepared as possible, and Day 4 was about notification," he told CNBC in an interview scheduled to air Monday. 
 
 Target was not the only US retailer to suffer a security breach during the holiday shopping season. Upscale department store Neiman Marcus confirmed on Friday that its database of customer information was hacked last month around the same time as the attack on Target. Additionally, Reuters reports that at least three other well-known but unidentified retailers experienced smaller breaches that have yet to be publicly revealed. 
 
 The practice of payment card skimming at point-of-sale terminals has become more frequent in recent years, often victimizing customers of well-known retailers. Bookseller Barnes & Noble discovered in fall 2012 that hackers had broken into keypads at more than 60 locations around the United States and made off with customers' credit card information. That same month, two Romanian men pled guilty to hacking point-of-sale terminals at hundreds of Subway sandwich stores in the US to steal credit card data from more than 146,000 accounts.
– It looks like the hackers that hit Target had lots of other, well, targets. The Department of Homeland Security recently sent retailers and financial service companies a secret memo warning that the Target hit appeared to be part of a larger international campaign, the Wall Street Journal reports, an insight gleaned with the help of Dallas cybersecurity firm iSight Partners. Yesterday, iSight released its own report, saying that a virus it's calling KAPTOXA "has potentially infected a large number of retail information systems"—and noting that the "intrusion operators displayed innovation and a high degree of skill," particularly in terms of the "operational sophistication" of the hack. The Journal shares this feature by way of example: The virus focused on stealing data during the peak hours of 10am and 5pm; the data was housed in a Target server that the hackers later accessed. The virus attacks point-of-sale systems in a way that is "new to eCrime," subverting traditional efforts to protect consumer data, the report warns, according to NBC. Parts of the code, which is impervious to all known antivirus software, have been online since last spring. It's partly in Russian, which US officials think may indicate a link to organized crime in the former Soviet Union. The finding follows reports of similar breaches at Neiman Marcus. That breach had gone unnoticed since July, the New York Times reports today; Neiman's system was only fully secured Sunday.