Fortinet Report: Cyberattackers Increase Use of Anti-Analysis, Evasion Tactics

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Fortinet recently released the Threat Landscape Report for Q2 of 2019 by FortiGuard Labs, the company’s threat intelligence and research arm. The research reveals that cybercriminals continue to look for new attack opportunities throughout the digital attack surface and are leveraging evasion as well as anti-analysis techniques as they become more sophisticated in their attempts.

Main Report Findings:

Many modern malware tools already incorporate features for evading antivirus or other threat detection measures, but cyber adversaries are becoming more sophisticated in their obfuscation and anti-analysis practices to avoid detection.

For example, a spam campaign demonstrates how adversaries are using and tweaking these techniques against defenders. The campaign involved the use of a phishing email with an attachment that turned out to be a weaponized Excel document with a malicious macro. The macro had attributes designed to disable security tools, execute commands arbitrarily, cause memory problems, and ensure that it would only run on Japanese systems. One property that it looked for in particular, an xlDate variable, seems to be undocumented.

Another example involves a variant of the Dridex banking Trojan which changed the names and hashes of files each time the victim logged in, making it difficult to spot the malware on infected host systems.

The growing use of anti-analysis and broader evasion tactics is a reminder of the need for multi-layered defenses and behavior-based threat detection.

The Zegost infostealer malware, is the cornerstone of a spear phishing campaign and contains intriguing techniques. Like other infostealers, the main objective of Zegost is to gather information about the victim’s device and exfiltrate it. Yet, when compared to other infostealers, Zegost is uniquely configured to stay under the radar. For example, Zegost includes functionality designed to clear event logs. This type of cleanup is not seen in typical malware. Another interesting development in Zegost’s evasion capabilities is a command that kept the infostealer “in stasis” until after February 14, 2019, after which it began its infection routine.

The threat actors behind Zegost utilize an arsenal of exploits to ensure they establish and maintain a connection to targeted victims, making it far more of a long term threat compared to its contemporaries. 

The attacks on multiple cities, local governments, and education systems serve as a reminder that ransomware is not going away, but instead continues to pose a serious threat for many organizations going forward. Ransomware attacks continue to move away from mass-volume, opportunistic attacks to more targeted attacks on organizations, which are perceived as having either the ability or the incentive to pay ransoms. In some instances, cybercriminals have conducted considerable reconnaissance before deploying their ransomware on carefully selected systems to maximize opportunity.

For example, RobbinHood ransomware is designed to attack an organization's network infrastructure and is capable of disabling Windows services that prevent data encryption and to disconnect from shared drives.

Another newer ransomware called Sodinokibi, could become another threat for organizations. Functionally, it is not very different from a majority of ransomware tools in the wild. It is troublesome because of the attack vector, which exploits a newer vulnerability that allows for arbitrary code execution and does not need any user interaction like other ransomware being delivered by phishing email.

Regardless of the vector, ransomware continues to pose a serious threat for organizations going forward, serving as a reminder of the importance of prioritizing patching and infosecurity awareness education. In addition, the increase of Remote Desktop Protocol (RDP) vulnerabilities, such as BlueKeep is a warning that remote access services can be opportunities for cybercriminals and that they can also be used as an attack vector to spread ransomware.

Between the home printer and critical infrastructure is a growing line of control systems for residential and small business use. These smart systems garner comparably less attention from attackers than their industrial counterparts, but that may be changing based on increased activity observed targeting these industrial control devices such as environmental controls, security cameras, and safety systems. A signature related to building management solutions was found to be triggered in 1% of organizations, which may not seem like much, but is much higher than typically seen for ICS or SCADA products.   

Cybercriminals are searching for new opportunities to commandeer control devices in homes and businesses. Sometimes these types of devices are not as prioritized as others or are outside the scope of traditional IT management. The security of smart residential and small business systems deserves elevated attention especially since access could have serious safety ramifications. This is especially relevant for remote work environments where secure access is important.

“The ever-widening breadth and sophistication of cyber adversaries’ attack methods is an important reminder of how they are attempting to leverage speed and connectivity to their advantage. Therefore, it is important for defenders to do the same and to relentlessly prioritize these important cybersecurity fundamentals, to position organizations to better manage and mitigate cyber risks,” said Fortinet’s CISO Phil Quade. “A security fabric approach across every security element that embraces segmentation and integration, actionable threat intelligence, and automation combined with machine learning is essential to enable these fundamentals to bear fruit.”