OATBOAT (Dropper) – Malware

Overview

OATBOAT is a sophisticated and stealthy malware trojan associated with the UNC1860 threat group, known for its ability to exploit vulnerabilities in internet-facing servers and deploy a range of malicious payloads. Operating as a key component in the group’s cyberattacks, OATBOAT plays a critical role in the group’s attack chain, facilitating the execution of additional malware once the initial access is gained through web shell deployment. This malware loader is designed to be highly evasive, executing shellcode payloads with minimal detection, making it particularly difficult for traditional security defenses to identify and block its activities.

What sets OATBOAT apart from other malicious trojans is its capability to operate without requiring a constant connection to command-and-control (C2) infrastructure, a technique often referred to as “passive” malware operations. By relying on the stealthy delivery of payloads through encrypted traffic, OATBOAT ensures that its actions remain concealed from network defenders, significantly complicating traditional detection and analysis methods. This approach allows the UNC1860 group to carry out operations with heightened operational security, reducing the likelihood of being detected by endpoint security tools or intrusion detection systems.

Targets

Information

Public Administration

How they operate

At a technical level, OATBOAT operates by first exploiting vulnerabilities in internet-facing servers to gain an initial foothold in a victim’s network. Once inside, the trojan executes a series of operations aimed at maintaining stealth and avoiding detection. OATBOAT’s design allows it to load and run shellcode directly on the infected system without triggering alarms or initiating outbound traffic to external C2 servers. This technique ensures that its activities remain concealed from traditional monitoring systems, which might otherwise flag unusual network behavior or external communications.

A key characteristic of OATBOAT is its use of encrypted communication to transfer payloads, making it difficult for security systems to inspect and block malicious traffic. By leveraging HTTPS-encrypted traffic, OATBOAT ensures that its commands and payloads cannot be easily extracted from intercepted network traffic. This makes the trojan highly resilient to traditional intrusion detection systems that rely on network traffic analysis to identify malicious activities.

Additionally, OATBOAT operates in a way that allows for the silent delivery of malicious payloads. Once the trojan is deployed on a target system, it can execute various shellcode payloads, which may include backdoors, keyloggers, or other types of malicious software. These payloads are often designed to establish a persistent presence on the infected system, ensuring that the attackers can maintain control over the network for an extended period. The trojan’s ability to evade detection, coupled with its flexibility in delivering multiple types of payloads, makes OATBOAT a critical enabler of UNC1860’s long-term cyber-espionage and data exfiltration campaigns.

OATBOAT’s evasion techniques extend beyond encrypted communication; it also uses advanced fileless execution methods, avoiding the need to write files to disk in a way that could trigger antivirus and endpoint detection systems. This fileless approach enables the trojan to stay hidden in memory and execute without leaving a trace on the filesystem, further complicating forensic analysis efforts. Moreover, OATBOAT leverages a modular architecture, meaning it can be easily adapted to load and execute various types of malware depending on the specific goals of the attackers, such as exfiltrating sensitive data or conducting further exploitation within the victim’s network.

The operational security of OATBOAT, with its ability to operate without outbound communications and utilize fileless techniques, underscores its role as a highly effective tool for advanced persistent threat (APT) groups like UNC1860. By maintaining a low profile and relying on stealthy operations, OATBOAT allows attackers to conduct long-term campaigns with minimal risk of detection. For organizations seeking to defend against such attacks, it is essential to employ advanced threat detection systems capable of monitoring memory activities, analyzing encrypted traffic, and identifying anomalies in network behavior to mitigate the risks posed by this sophisticated trojan.

References

• UNC1860 and the Temple of Oats: Iran’s Hidden Hand in Middle Eastern Networks