Sophos: Abuse of Trusted Applications Surges

Sophos has released an in-depth look at the changing behaviors and attack techniques that adversaries used in the first half of 2024. The UK-based cybersecurity company’s research found that attackers are leveraging trusted applications and tools on Windows systems, commonly called “living off the land” binaries, to conduct discovery on systems and maintain persistence. When compared to 2023, Sophos saw a 51% increase in abusing “Living off the Land” binaries or LOLbins. When the data set is expanded through 2021, the increase is measured at 83%.

Among the 187 unique Microsoft LOLbins detected in the first half of the year, the most frequently abused trusted application was remote desktop protocol (RDP). Of the nearly 200 IR cases analyzed, attackers abused RDP in 89% of them. This dominance continues a trend first observed in the 2023 Active Adversary report in which RDP abuse was prevalent in 90% of all IR cases investigated.

“While abusing some legitimate tools might raise a few defenders’ eyebrows, and hopefully some alerts, abusing a Microsoft binary often has the opposite effect,” said Sophos Field CTO John Shier. “Many of these abused Microsoft tools are integral to Windows and have legitimate uses, but it’s up to system administrators to understand how they are used in their environments and what constitutes abuse. Without nuanced and contextual awareness of the environment, including continuous vigilance to new and developing events within the network, today’s stretched IT teams risk missing key threat activity that often leads to ransomware.”

Among the key findings, compromised credentials are still the number one root cause of attacks, accounting for the root cause in 39% of cases. This is, however, a decline from the 56% noted in 2023. Meanwhile, dwell time (the time from when an attack starts to when it’s detected) has remained approximately eight days. However, with MDR, the median dwell time is just one day for all types of incidents and only three days for ransomware attacks. Attackers most frequently compromised the 2019, 2016, and 2012 server versions of Active Directory (AD). All three of these versions are now out of mainstream Microsoft support—one step before they become end-of-life (EOL) and impossible to patch without paid support from Microsoft. In addition, a full 21% of the AD server versions compromised were already EOL.

The data is derived from nearly 200 incident response (IR) cases from across both the Sophos X-Ops IR team and Sophos X-Ops Managed Detection and Response (MDR) team. For readers seeking additional information, the report is entitled, “The Bite from Inside: The Sophos Active Adversary Report.”

Channel Impact^®
Channel partners can go a long way towards solidifying customer relationships by building a knowledge base around widely used attack vectors such as the ones covered in the Sophos report.