Ursnif

Ursnif is a type of malware primarily known for its capabilities as a banking trojan. It is designed to steal sensitive information such as banking credentials, personal data, and other confidential information from infected systems. Ursnif has evolved over time, incorporating various functionalities that enhance its ability to evade detection and increase its impact. As of October 2023, Ursnif remains a significant threat to individuals and organizations globally, with various campaigns targeting different sectors.

Overview

Ursnif, also known as Gozi or ISFB, is a malware family that primarily functions as a banking trojan. It targets Windows operating systems and is designed to steal sensitive information, including banking credentials, from infected systems. Ursnif has been active for several years and has undergone numerous iterations, each adding new features and capabilities. The malware is often distributed through phishing emails and malicious attachments, making it a persistent threat to both individuals and organizations.

History

Ursnif first emerged in the wild in the mid-2000s. Initially, it was a simple banking trojan, but over time, it has evolved into a more sophisticated piece of malware. The source code for Ursnif was leaked in 2010, which led to the development of various variants by different threat actors. These variants have been used in numerous campaigns, targeting a wide range of sectors, including finance, healthcare, and government.

Technical characteristics

Ursnif is known for its modular architecture, which allows it to incorporate various functionalities. It typically includes features such as keylogging, form grabbing, and screenshot capturing. These capabilities enable Ursnif to steal sensitive information from infected systems. The malware also employs various techniques to evade detection, such as code obfuscation and the use of encryption to protect its communications with command and control (C2) servers.

Infection vector

Ursnif is primarily distributed through phishing emails that contain malicious attachments or links. These emails often appear to be from legitimate sources, tricking recipients into opening them. Once the attachment is opened or the link is clicked, the malware is downloaded and executed on the victim's system. Ursnif can also spread through exploit kits, which take advantage of vulnerabilities in software to deliver the malware.

Notable campaigns

Over the years, Ursnif has been involved in numerous campaigns targeting various sectors. One notable campaign occurred in 2016, when Ursnif was used to target financial institutions in Japan. The campaign involved phishing emails that appeared to be from legitimate Japanese banks, tricking recipients into downloading the malware. Another significant campaign took place in 2018, when Ursnif was used to target healthcare organizations in the United States. This campaign involved phishing emails that contained malicious Microsoft Word documents, which, when opened, executed macros to download and install the malware.

Detection and mitigation

Detecting Ursnif can be challenging due to its use of obfuscation and encryption techniques. However, organizations can implement several measures to mitigate the risk of infection. These include deploying antivirus software, conducting regular security audits, and educating employees about the dangers of phishing emails. Additionally, organizations can implement network monitoring to detect unusual activity that may indicate the presence of Ursnif or other malware.

See also

• Lateral movement

Sources

• Ursnif - MITRE ATT&CK
• CISA Alert on Ursnif
• NIST National Vulnerability Database
• Securelist Ursnif Analysis

This article provides an overview of Ursnif, its history, technical characteristics, infection vectors, notable campaigns, and methods for detection and mitigation. Ursnif remains a significant threat, and understanding its operation is crucial for effective cybersecurity measures.