Facebook said on Thursday that it had taken down about 200 accounts run by an Iranian hacking group, known as “Tortoiseshell”, as part of a cyber-spying operation that primarily targeted US military personnel and people working at defence and aerospace firms.
“This group used various malicious tactics to identify its targets & infect their devices with malware to enable espionage.”
“This activity had the hallmarks of a well-resourced & persistent operation, while relying on relatively strong operational security measures to hide who’s behind it” per Facebook.
The Iran-based Tortoiseshell hackers also “created a set of tailored domains designed to attract particular targets. Among them were fake recruiting websites for particular defense companies, as per Facebook.
Facebook identified the following tactics, techniques and procedures used by Iranian hackers across the internet. Here’s how Facebook said, they identified the hackers’ TTPs:
Social engineering: In running its highly targeted campaign, Tortoiseshell deployed sophisticated fake online personas to contact its targets, build trust and trick them into clicking on malicious links. These fictitious personas had profiles across multiple social media platforms to make them appear more credible. These accounts often posed as recruiters and employees of defense and aerospace companies from the countries their targets were in. Other personas claimed to work in hospitality, medicine, journalism, NGOs and airlines. They leveraged various collaboration and messaging platforms to move conversations off-platform and send malware to their targets. Our investigation found that this group invested significant time into their social engineering efforts across the internet, in some cases engaging with their targets for months.
Phishing and credential theft: This group created a set of tailored domains designed to attract particular targets within the aerospace and defense industries. Among them were fake recruiting websites for particular defense companies. They also set up online infrastructure that spoofed a legitimate US Department of Labor job search site. As part of their phishing campaigns, they spoofed domains of major email providers and mimicked URL-shortening services, likely to conceal the final destination of these links. These domains appeared to have been used for stealing login credentials to the victims’ online accounts (e.g. corporate and personal email, collaboration tools, social media). They also appeared to be used to profile their targets’ digital systems to obtain information about people’s devices, networks they connected to and the software they installed to ultimately deliver target-tailored malware.
Malware: This group used custom malware tools we believe to be unique to their operations, including full-featured remote-access trojans, device and network reconnaissance tools and keystroke loggers. Among these tools, they continued to develop and modify their malware for Windows known as Syskit, which they’ve used for years. They also shared links to malicious Microsoft Excel spreadsheets, which enabled malware to perform various system commands to profile the victim’s machine in a manner very similar to the Liderc reconnaissance tool identified by researchers at Cisco. One previously unreported variant of the malicious tool was embedded in a Microsoft Excel document and was capable of writing the output (i.e. result of the system reconnaissance) to a hidden area of the spreadsheet, which presumably required an attacker to social engineer the target to trick them into saving and returning the file.
Outsourcing malware development: We’ve observed this group use several distinct malware families. Our investigation and malware analysis found that a portion of their malware was developed by Mahak Rayan Afraz (MRA), an IT company in Tehran with ties to the Islamic Revolutionary Guard Corps (IRGC). Some of the current and former MRA executives have links to companies sanctioned by the US government.
We shared our findings and threat indicators with industry peers so they too can detect and mitigate this activity. To disrupt this operation, we blocked malicious domains from being shared on our platform, took down the group’s accounts and notified people who we believe were targeted by this threat actor.