iPhones Increasingly Vulnerable to Coinhive Cryptomining Malware

Apple's iPhones are increasingly becoming a target of bad actors using the popular Coinhive malware designed to steal CPU cycles to illegally mine for cryptocurrencies, according to researchers at Check Point.

In the cybersecurity solution provider's most recent Global Threat Index, the researchers found an almost 400% increase in cryptomining attacks against iPhones, particularly during the last two weeks of September.

The rise in attacks on the Apple smartphone coincided with a significant increase in attacks against people using the Apple Safari browser.

The researchers found that were unsure of the reason behind the growth in attacks against the iPhone and noted that the attacks aren't using new functionalities in the campaigns. However, the attackers are using Coinhive, which was first seen in September 2017 and has been atop Check Point's index since December. Coinhive is the most popular malware for cryptomining, which itself has become the most dominant threat against enterprises since late last year, overtaking ransomware.

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In a blog post outlining the findings in Check Point's index, researchers wrote that the increased attacks on iPhones "serves to remind us that mobile devices are an often-overlooked element of an organization's attack surface. It's critical that mobile devices are protected with a comprehensive threat prevention solution, to stop them being the weak point in corporate security defenses."

In an email to Security Now, Omer Dembinsky, Check Point's team leader for products R&D and data research, wrote that that "cryptomining activity has been witnessed in the past on Apple devices (although in lower volumes), and it is by no means immune to these type of attacks. It is true that many of the mobile cyber threats are more targeted towards Android, but as cyber criminals are always looking for ways to expand their reach, it is very possible to see these types of sudden spikes if a specific effort is done by the attacking side."

The reach of Coinhive continues to be strong. The analysts found that the mining malware now impacts 19% of organizations around the world, a status that was accomplished in just over a year. The popularity of the malware comes in part from efforts to get the name into the market, Dembinsky said. (See Cryptomining Malware, Cryptojacking Remain Top Security Threats.)

"Coinhive was the first 'brand' of cryptominer to make a name for itself, and as such is many times the default choice by threat actors," he wrote.

Cryptoloot is another mining malware that is emerging as a competitor to Coinhive. Like other cryptomining malware, Cryptoloot uses the CPU or GPU power of a victim's system and resources that reside in it to mine for cryptocurrencies like Bitcoin, Monero and Ethereum. The researchers wrote that Cryptoloot is "trying to pull the rug under [Coinhive] by asking a lower percentage of revenue from websites."

"The Cryptoloot strategy was the same since the beginning as part of trying to compete in the field," Dembinsky told Security Now. "The situation is very similar to many markets where there is a strong product (Coinhive in this case) and the others try to employ different strategies to compete."

Coinhive and Cryptoloot were not the only mining malware in Check Point's list of the Top 10 "most wanted" malware. Also included on the list were:

Trojans aimed at financial institutions also were popular on Check Point's list. Included in the Top 10 was Ramnit, a banking Trojan that steals banking credentials, FTP passwords, session cookies and personal data, and Emotet, a Trojan that targets Windows-based systems and attacks customers of certain bands. It uses various APIs to monitor and log network traffic, then create a Run key registry entry to get started once the system reboots, according to researchers.

Ramnit and Emotet are examples of the rising popularity of banking Trojans among threat actors. Researchers with Proofpoint and Kaspersky Lab in separate reports noted a rise in the use of banking Trojans, with Proofpoint analysts saying banking Trojans were the most popular type of malware in the second quarter, accounting for 42% of malware the company had detected. (See DanaBot Banking Trojan Is Now Finding Its Way to the US.)

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— Jeffrey Burt is a long-time tech journalist whose work has appeared in such publications as eWEEK, The Next Platform and Channelnomics.