Hackers Exploit Emails on Exchange Servers Without Proper Patching
Table of Contents
- By Patrick Ryan
- Mar 28, 2022
Hackers are spreading malware through the hijacking of email chains on exchange servers lacking the necessary patching. This emerging email phishing effort uses conversation tactics to take control, transmitting IcedID malware that steals information. The malware is delivered to target machines through Microsoft Exchange servers that are exposed to the public and unpatched.
How is the Attack Performed?
The email attack relies on a social engineering strategy referred to as conversation hijacking, sometimes called thread hijacking. Intezer, an Israel-based company, recently revealed the details of this unique attack. Representatives from Intezer shared the information with the Hacker News, stating that forged replies to emails that were stolen persuade targets to open attachments. The opening of one or several attachments makes the phishing message seem that much more legitimate, ultimately spurring an elevated infection rate.
What is the Purpose of the Attack?
The aim of this attack is to send fake replies to email threads with the use of the compromised party’s email account through that individual’s email address, creating the impression that the messages are legitimate. Such conversation hijacking is a manipulative social engineering strategy that heightens the chances of the phishing attempt fooling targets into taking the suggested action.
Who Does the Attack Target?
The latest string of attacks, first identified at the start of March, is zeroing in on businesses in the pharmaceutical, law, healthcare, and energy sectors.
What is IcedID all About?
IcedID, also known as BokBot, is a banking trojan that serves as an entry point for advanced threats. IcedID is similar to the Cobalt Strike adversary attack and ransomware operated by human hackers as it sets the stage for the implementation of advanced threats.
IcedID is advanced to the point that it connects to remote servers and downloads what are referred to as “next stage implants” along with other tools that empower hackers to execute follow-on activities, shifting across the entirety of the compromised networks to transmit more malware.
When was IcedID First Implemented?
Rewind to the summer of 2021, and word first broke about initial stage malware payloads, including the likes of IcedID to implement REvil, Maze, and Egregor ransomware. Proofpoint first reported the news of the IcedID attack. Proofpoint representatives state this unique evolving tactic centered on access brokers venturing into victim networks through IcedID and other malware payloads.
Interestingly, the initial IcedID campaigns used contact forms from websites to transmit links containing malware to target businesses. However, the latest version of IcedID compromises banks on susceptible Microsoft Exchange servers to transmit emails from compromised accounts, meaning the social engineering manipulation is evolving as time progresses.
According to digital security researchers Ryan Robinson and Joakim Kennedy, the IcedID payload is transitioning away from Office documents to ISO files with a DLL and Windows LNK file. The strategic use of the ISO files empowers threat actors to sidestep controls dubbed “Mark-of-the-Web,” spurring the malware’s execution without providing the target user with any sort of warning.
How Can the Attack be Prevented?
Aside from providing your team with guidance pertaining to identifying digital security scams, it will also help to update your digital security defenses. In particular, the addition of the latest patches from a trusted digital security services provider will help prevent an infiltration.