The Lazarus Group has been discovered behind a new cyberattack campaign dubbed HaoBao targeting banks and Bitcoin users via spear phishing lures that deliver a new cryptocurrency scanner that hunts for Bitcoin wallets.
The attack campaign uses spear-phishing emails impersonating job recruiters, a tactic previously seen from the group - widely believed by researchers to operate out of North Korea - last year. From April through October 2017, researchers at McAfee Advanced Threat Research (ATR) saw Lazarus Group using job descriptions to target a range of organizations in English and Korean, gain access to their environments, and then steal sensitive data or money.
In January 2018, researchers detected the start of a new campaign when they found a malicious document disguised as job recruitment for a business development executive located in Hong Kong. More malicious files with the same "Windows User" author appeared from January 16-24.
While the fake job recruitment messages are similar to those seen last year, the implants in this campaign have never been previously seen in the wild or used in previous Lazarus Group attacks, says Ryan Sherstobitoff, McAfee senior analyst of malware campaigns.
When a victim selects "enable content," the malicious document launches one of two payloads on the system via a Visual Basic macro. The first is a lightweight cryptocurrency scanner, which gathers data on processes and users then scans for a registry key and Bitcoin wallet. Attackers can observe traffic sent to the C&C server to determine whether a machine uses Bitcoin or not.
"It's being more focused and filtering out targets of interest," Sherstobitoff explains. "They're getting more aggressive with Bitcoin stealing, and more aggressive in the way they target."
If the malware detects a machine has a Bitcoin wallet, it deploys and installs another payload. The secondary payload is a long-term implant intended to gain persistence on the machine. While researchers weren't able to observe this directly, he says this second stage probably has capabilities to steal private keys or siphon from the victim's Bitcoin wallet.
Sherstobitoff says this campaign demonstrates Lazarus Group is moving toward smaller implants as opposed to large files and installations it used in the past. HaoBao loads directly into memory to scan information, making forensics recovery more difficult.
"They're going fileless, and going for reduced implants, and reducing the footprint overall on the machine and cleaning up more quickly," he says of their change in tactics. Moving forward, he expects they'll continue to shrink their presence so it's as small as needed to be successful.
Antivirus tools would detect this implant but overall, discovery is difficult because the attack is fairly targeted, says Sherstobitoff. "If your AV products aren't totally up-to-date, there's high potential these things can go for a number of days or months without being seen."
Further, attackers may use data from the initial scan to tailor their secondary payload. For example, he continues, if the scanner determines a system is running a certain type of antivirus software, attackers could craft the second stage to evade detection.
There have been signs of increased activity from Lazarus Group, which researchers believe is based in North Korea. The US-CERT today published an advisory stating the DHS and FBI have detected Trojan malware variants HARDRAIN and BADCALL used by the North Korean government. The US government refers to North Korean cyber activity as Hidden Cobra, another term for the group.
Going for Gold
Previous Lazarus Group campaigns from 2017 focused on both money and data theft. This time, it seems their focus is exclusively on Bitcoin. HaoBao is used to target financial organizations and institutions that use or trade Bitcoin, which might have wallets, Sherstobitoff says.
He points out that only two organizations were used as a lure in the spear-phishing emails used in this attack. The job descriptions used in fraudulent emails are legitimate positions taken from real career sites. While the targets are unknown, all are related to cryptocurrency.
Cryptocurrency is a growing target for attackers because it's highly anonymous, and there aren't many regulations that make catching crypto theft east. Many attackers have found it's more lucrative for them to steal compute power for mining cryptocurrencies, as opposed to stealing data, says RedLock CEO Varun Badhwar. Cryptojacking attacks on businesses often go unnoticed.
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