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For nearly a dozen years, residents of South Carolina have been kept in the dark by state and federal investigators over who was responsible for hacking into the state’s revenue department in 2012 and stealing tax and bank account information for 3.6 million people. The answer may no longer be a mystery: KrebsOnSecurity found compelling clues suggesting the intrusion was carried out by the same Russian hacking crew that stole of millions of payment card records from big box retailers like Home Depot and Target in the years that followed.
Questions about who stole tax and financial data on roughly three quarters of all South Carolina residents came to the fore last week at the confirmation hearing of Mark Keel, who was appointed in 2011 by Gov. Nikki Haley to head the state’s law enforcement division. If approved, this would be Keel’s third six-year term in that role.
The Associated Press reports that Keel was careful not to release many details about the breach at his hearing, telling lawmakers he knows who did it but that he wasn’t ready to name anyone.
“I think the fact that we didn’t come up with a whole lot of people’s information that got breached is a testament to the work that people have done on this case,” Keel asserted.
A ten-year retrospective published in 2022 by The Post and Courier in Columbia, S.C. said investigators determined the breach began on Aug. 13, 2012, after a state IT contractor clicked a malicious link in an email. State officials said they found out about the hack from federal law enforcement on October 10, 2012.
KrebsOnSecurity examined posts across dozens of cybercrime forums around that time, and found only one instance of someone selling large volumes of tax data in the year surrounding the breach date.
On Oct. 7, 2012 — three days before South Carolina officials say they first learned of the intrusion — a notorious cybercriminal who goes by the handle “Rescator” advertised the sale of “a database of the tax department of one of the states.”
“Bank account information, SSN and all other information,” Rescator’s sales thread on the Russian-language crime forum Embargo read. “If you purchase the entire database, I will give you access to it.”
A week later, Rescator posted a similar offer on the exclusive Russian forum Mazafaka, saying he was selling information from a U.S. state tax database, without naming the state. Rescator said the data exposed included Social Security Number (SSN), employer, name, address, phone, taxable income, tax refund amount, and bank account number.
“There is a lot of information, I am ready to sell the entire database, with access to the database, and in parts,” Rescator told Mazafaka members. “There is also information on corporate taxpayers.”
On Oct. 26, 2012, the state announced the breach publicly. State officials said they were working with investigators from the U.S. Secret Service and digital forensics experts from Mandiant, which produced an incident report (PDF) that was later published by South Carolina Dept. of Revenue. KrebsOnSecurity sought comment from the Secret Service, South Carolina prosecutors, and Mr. Keel’s office. This story will be updated if any of them respond. Update: The Secret Service declined to comment.
On Nov. 18, 2012, Rescator told fellow denizens of the forum Verified he was selling a database of 65,000 records with bank account information from several smaller, regional financial institutions. Rescator’s sales thread on Verified listed more than a dozen database fields, including account number, name, address, phone, tax ID, date of birth, employer and occupation.
Asked to provide more context about the database for sale, Rescator told forum members the database included financial records related to tax filings of a U.S. state. Rescator added that there was a second database of around 80,000 corporations that included social security numbers, names and addresses, but no financial information.
The AP says South Carolina paid $12 million to Experian for identity theft protection and credit monitoring for its residents after the breach.
“At the time, it was one of the largest breaches in U.S. history but has since been surpassed greatly by hacks to Equifax, Yahoo, Home Depot, Target and PlayStation,” the AP’s Jeffrey Collins wrote.
As it happens, Rescator’s criminal hacking crew was directly responsible for the 2013 breach at Target and the 2014 hack of Home Depot. The Target intrusion saw Rescator’s cybercrime shops selling roughly 40 million stolen payment cards, and 56 million cards from Home Depot customers.
Who is Rescator? On Dec. 14, 2023, KrebsOnSecurity published the results of a 10-year investigation into the identity of Rescator, a.k.a. Mikhail Borisovich Shefel, a 36-year-old who lives in Moscow and who recently changed his last name to Lenin.
Mr. Keel’s assertion that somehow the efforts of South Carolina officials following the breach may have lessened its impact on citizens seems unlikely. The stolen tax and financial data appears to have been sold openly on cybercrime forums by one of the Russian underground’s most aggressive and successful hacking crews.
While there are no indications from reviewing forum posts that Rescator ever sold the data, his sales threads came at a time when the incidence of tax refund fraud was skyrocketing.
Tax-related identity theft occurs when someone uses a stolen identity and SSN to file a tax return in that person’s name claiming a fraudulent refund. Victims usually first learn of the crime after having their returns rejected because scammers beat them to it. Even those who are not required to file a return can be victims of refund fraud, as can those who are not actually owed a refund from the U.S. Internal Revenue Service (IRS).
According to a 2013 report from the Treasury Inspector General’s office, the IRS issued nearly $4 billion in bogus tax refunds in 2012, and more than $5.8 billion in 2013. The money largely was sent to people who stole SSNs and other information on U.S. citizens, and then filed fraudulent tax returns on those individuals claiming a large refund but at a different address.
It remains unclear why Shefel has never been officially implicated in the breaches at Target, Home Depot, or in South Carolina. It may be that Shefel has been indicted, and that those indictments remain sealed for some reason. Perhaps prosecutors were hoping Shefel would decide to leave Russia, at which point it would be easier to apprehend him if he believed no one was looking for him.
But all signs are that Shefel is deeply rooted in Russia, and has no plans to leave. In January 2024, authorities in Australia, the United States and the U.K. levied financial sanctions against 33-year-old Russian man Aleksandr Ermakov for allegedly stealing data on 10 million customers of the Australian health insurance giant Medibank.
A week after those sanctions were put in place, KrebsOnSecurity published a deep dive on Ermakov, which found that he co-ran a Moscow-based IT security consulting business along with Mikhail Shefel called Shtazi-IT.
A Google-translated version of Shtazi dot ru. Image: Archive.org.
Authorities in Australia, the United Kingdom and the United States this week levied financial sanctions against a Russian man accused of stealing data on nearly 10 million customers of the Australian health insurance giant Medibank. 33-year-old Aleksandr Ermakov allegedly stole and leaked the Medibank data while working with one of Russia’s most destructive ransomware groups, but little more is shared about the accused. Here’s a closer look at the activities of Mr. Ermakov’s alleged hacker handles.
Aleksandr Ermakov, 33, of Russia. Image: Australian Department of Foreign Affairs and Trade.
The allegations against Ermakov mark the first time Australia has sanctioned a cybercriminal. The documents released by the Australian government included multiple photos of Mr. Ermakov, and it was clear they wanted to send a message that this was personal.
It’s not hard to see why. The attackers who broke into Medibank in October 2022 stole 9.7 million records on current and former Medibank customers. When the company refused to pay a $10 million ransom demand, the hackers selectively leaked highly sensitive health records, including those tied to abortions, HIV and alcohol abuse.
The U.S. government says Ermakov and the other actors behind the Medibank hack are believed to be linked to the Russia-backed cybercrime gang REvil.
“REvil was among the most notorious cybercrime gangs in the world until July 2021 when they disappeared. REvil is a ransomware-as-a-service (RaaS) operation and generally motivated by financial gain,” a statement from the U.S. Department of the Treasury reads. “REvil ransomware has been deployed on approximately 175,000 computers worldwide, with at least $200 million paid in ransom.”
The sanctions say Ermakov went by multiple aliases on Russian cybercrime forums, including GustaveDore, JimJones, and Blade Runner. A search on the handle GustaveDore at the cyber intelligence platform Intel 471 shows this user created a ransomware affiliate program in November 2021 called Sugar (a.k.a. Encoded01), which focused on targeting single computers and end-users instead of corporations.
An ad for the ransomware-as-a-service program Sugar posted by GustaveDore warns readers against sharing information with security researchers, law enforcement, or “friends of Krebs.”
In November 2020, Intel 471 analysts concluded that GustaveDore’s alias JimJones “was using and operating several different ransomware strains, including a private undisclosed strain and one developed by the REvil gang.”
In 2020, GustaveDore advertised on several Russian discussion forums that he was part of a Russian technology firm called Shtazi, which could be hired for computer programming, web development, and “reputation management.” Shtazi’s website remains in operation today.
A Google-translated version of Shtazi dot ru. Image: Archive.org.
The third result when one searches for shtazi[.]ru in Google is an Instagram post from a user named Mikhail Borisovich Shefel, who promotes Shtazi’s services as if it were also his business. If this name sounds familiar, it’s because in December 2023 KrebsOnSecurity identified Mr. Shefel as “Rescator,” the cybercriminal identity tied to tens of millions of payment cards that were stolen in 2013 and 2014 from big box retailers Target and Home Depot, among others.
How close was the connection between GustaveDore and Mr. Shefel? The Treasury Department’s sanctions page says Ermakov used the email address ae.ermak@yandex.ru. A search for this email at DomainTools.com shows it was used to register just one domain name: millioner1[.]com. DomainTools further finds that a phone number tied to Mr. Shefel (79856696666) was used to register two domains: millioner[.]pw, and shtazi[.]net.
The December 2023 story here that outed Mr. Shefel as Rescator noted that Shefel recently changed his last name to “Lenin” and had launched a service called Lenin[.]biz that sells physical USSR-era Ruble notes bearing the image of Vladimir Lenin, the founding father of the Soviet Union. The Instagram account for Mr. Shefel includes images of stacked USSR-era Ruble notes, as well as multiple links to Shtazi.
The Instagram account of Mikhail Borisovich Shefel, aka MikeMike aka Rescator.
Intel 471’s research revealed Ermakov was affiliated in some way with REvil because the stolen Medibank data was published on a blog that had one time been controlled by REvil affiliates who carried out attacks and paid an affiliate fee to the gang.
But by the time of the Medibank hack, the REvil group had mostly scattered after a series of high-profile attacks led to the group being disrupted by law enforcement. In November 2021, Europol announced it arrested seven REvil affiliates who collectively made more than $230 million worth of ransom demands since 2019. At the same time, U.S. authorities unsealed two indictments against a pair of accused REvil cybercriminals.
“The posting of Medibank’s data on that blog, however, indicated a connection with that group, although the connection wasn’t clear at the time,” Intel 471 wrote. “This makes sense in retrospect, as Ermakov’s group had also been a REvil affiliate.”
It is easy to dismiss sanctions like these as ineffective, because as long as Mr. Ermakov remains in Russia he has little to fear of arrest. However, his alleged role as an apparent top member of REvil paints a target on him as someone who likely possesses large sums of cryptocurrency, said Patrick Gray, the Australian co-host and founder of the security news podcast Risky Business.
“I’ve seen a few people poo-poohing the sanctions…but the sanctions component is actually less important than the doxing component,” Gray said. “Because this guy’s life just got a lot more complicated. He’s probably going to have to pay some bribes to stay out of trouble. Every single criminal in Russia now knows he is a vulnerable 33 year old with an absolute ton of bitcoin. So this is not a happy time for him.”
Update, Feb. 21, 1:10 p.m. ET: The Russian security firm F.A.C.C.T reports that Ermakov has been arrested in Russia, and charged with violating domestic laws that prohibit the creation, use and distribution of malicious computer programs.
“During the investigation, several defendants were identified who were not only promoting their ransomware, but also developing custom-made malicious software, creating phishing sites for online stores, and driving user traffic to fraudulent schemes popular in Russia and the CIS,” F.A.C.C.T. wrote. “Among those detained was the owner of the nicknames blade_runner, GistaveDore, GustaveDore, JimJones.”
Researchers say mobile malware purveyors have been abusing a bug in the Google Android platform that lets them sneak malicious code into mobile apps and evade security scanning tools. Google says it has updated its app malware detection mechanisms in response to the new research.
At issue is a mobile malware obfuscation method identified by researchers at ThreatFabric, a security firm based in Amsterdam. Aleksandr Eremin, a senior malware analyst at the company, told KrebsOnSecurity they recently encountered a number of mobile banking trojans abusing a bug present in all Android OS versions that involves corrupting components of an app so that its new evil bits will be ignored as invalid by popular mobile security scanning tools, while the app as a whole gets accepted as valid by Android OS and successfully installed.
“There is malware that is patching the .apk file [the app installation file], so that the platform is still treating it as valid and runs all the malicious actions it’s designed to do, while at the same time a lot of tools designed to unpack and decompile these apps fail to process the code,” Eremin explained.
Eremin said ThreatFabric has seen this malware obfuscation method used a few times in the past, but in April 2023 it started finding many more variants of known mobile malware families leveraging it for stealth. The company has since attributed this increase to a semi-automated malware-as-a-service offering in the cybercrime underground that will obfuscate or “crypt” malicious mobile apps for a fee.
Eremin said Google flagged their initial May 9, 2023 report as “high” severity. More recently, Google awarded them a $5,000 bug bounty, even though it did not technically classify their finding as a security vulnerability.
“This was a unique situation in which the reported issue was not classified as a vulnerability and did not impact the Android Open Source Project (AOSP), but did result in an update to our malware detection mechanisms for apps that might try to abuse this issue,” Google said in a written statement.
Google also acknowledged that some of the tools it makes available to developers — including APK Analyzer — currently fail to parse such malicious applications and treat them as invalid, while still allowing them to be installed on user devices.
“We are investigating possible fixes for developer tools and plan to update our documentation accordingly,” Google’s statement continued.
Image: ThreatFabric.
According to ThreatFabric, there are a few telltale signs that app analyzers can look for that may indicate a malicious app is abusing the weakness to masquerade as benign. For starters, they found that apps modified in this way have Android Manifest files that contain newer timestamps than the rest of the files in the software package.
More critically, the Manifest file itself will be changed so that the number of “strings” — plain text in the code, such as comments — specified as present in the app does match the actual number of strings in the software.
One of the mobile malware families known to be abusing this obfuscation method has been dubbed Anatsa, which is a sophisticated Android-based banking trojan that typically is disguised as a harmless application for managing files. Last month, ThreatFabric detailed how the crooks behind Anatsa will purchase older, abandoned file managing apps, or create their own and let the apps build up a considerable user base before updating them with malicious components.
ThreatFabric says Anatsa poses as PDF viewers and other file managing applications because these types of apps already have advanced permissions to remove or modify other files on the host device. The company estimates the people behind Anatsa have delivered more than 30,000 installations of their banking trojan via ongoing Google Play Store malware campaigns.
Google has come under fire in recent months for failing to more proactively police its Play Store for malicious apps, or for once-legitimate applications that later go rogue. This May 2023 story from Ars Technica about a formerly benign screen recording app that turned malicious after garnering 50,000 users notes that Google doesn’t comment when malware is discovered on its platform, beyond thanking the outside researchers who found it and saying the company removes malware as soon as it learns of it.
“The company has never explained what causes its own researchers and automated scanning process to miss malicious apps discovered by outsiders,” Ars’ Dan Goodin wrote. “Google has also been reluctant to actively notify Play users once it learns they were infected by apps promoted and made available by its own service.”
The Ars story mentions one potentially positive change by Google of late: A preventive measure available in Android versions 11 and higher that implements “app hibernation,” which puts apps that have been dormant into a hibernation state that removes their previously granted runtime permissions.
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