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 The computer network at Neiman Marcus was penetrated by hackers as far back as July, and the breach was not fully contained until Sunday, according to people briefed on the investigation. 
 
 
 
 
 
 
 
 
 
 The company disclosed the data theft of customer information late last week, saying it first learned in mid-December of suspicious activity that involved credit cards used at its stores. It issued another notice on Thursday, elaborating slightly. 
 
 The latest notice said that “some of our customers’ payment cards were used fraudulently after making purchases at our stores. We have taken steps to notify those affected customers for whom we have contact information.” 
 
 The company apologized again, and said it did not believe the customers’ Social Security numbers or birth dates — key pieces of personal data — had been compromised. 
 
 Neiman Marcus defended its decision not to disclose anything until last week, saying it waited to confirm evidence. The company said nothing about when the attack began and when it was contained. 
 
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 In a call with credit card companies on Monday, though, Neiman acknowledged that the attack had only been fully contained a day earlier, and that the time stamp on the first intrusion was in mid-July, people briefed on the call said, speaking on the condition of anonymity because of the investigation. 
 
 The issue at Neiman appears to have gone on for significantly longer than the widespread attack on Target. In Target’s case, however, the data that was stolen appears to be much more significant and ripe for fraud. Target has said card numbers from 40 million customers were stolen, along with encrypted PINs for debit cards. It also estimated that other personal information belonging to 70 million people had been stolen by the hackers. 
 
 Neiman Marcus said on Thursday that it had “no knowledge of any connection” between its data breach and Target’s. 
 
 Neiman has not publicly given any estimate of how many credit card numbers were stolen, or how many customers were affected. But it noted that it does not collect PINs in its stores. 
 
 The company only publicly acknowledged the data breach last Friday after facing inquiries from a journalist specializing in computer security, Brian Krebs. 
 
 But Neiman had told credit card companies around Christmas, in an industry phone call, that it had evidence that credit cards used at Neiman Marcus were being used to make fraudulent purchases, people who were briefed on those phone calls said. 
 
 Neiman has faced criticism for not telling customers about the breach sooner. Target informed its customers about its attack within a few days of learning about it for the first time, pushed also by inquiries from Mr. Krebs. Target’s acknowledgment came right before the final holiday shopping weekend, and put a significant dent in Target’s sales in the final seasonal rush. 
 
 Some people briefed on the investigation questioned Neiman’s decision not to disclose anything to the public until the shopping season was over. 
 
 One person briefed by law enforcement on the investigation noted: “January 1 is conveniently timed after the holiday season.” 
 
 A spokeswoman for Neiman Marcus, Ginger Reeder, asserted on Thursday that the holiday season had nothing to do with its decision. 
 
 In its notice on Thursday, the company said: “We quickly began our investigation and hired a forensic investigator. Our forensic investigator discovered evidence on Jan. 1st that a criminal cybersecurity intrusion had occurred. The forensic and criminal investigations continue.” Neiman said it would provide customers with one free year of credit monitoring, similar to what Target has offered. 
 
 A growing group of state attorneys general, including those from Connecticut, New York and Illinois, are jointly investigating both the Target and Neiman Marcus breaches. 
 
 The authorities are examining whether the two attacks are related. Both appear to have been committed by criminal groups in Eastern Europe, people briefed on the investigation said. ||||| 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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 ||||| The holiday data breach at Target Corp. appeared to be part of a broad and highly sophisticated international hacking campaign against multiple retailers, according to a report prepared by federal and private investigators that was sent to financial-services companies and retailers. 
 
 The report offers some of the first details to emerge about the source of the attack that compromised 40 million credit- and debit-card accounts and...
– 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.