Security researchers observed that a new Ursnif attack campaign replaced PowerShell with mshta as a means to distribute the malware.

Zscaler observed that the Ursnif campaign began with the delivery of document files bearing the name “info_03_24.doc.” These documents leveraged malicious Visual Basic for Applications (VBA) macro code to call the main routine. This stage involved writing the second-stage payload to “index.html” and executing it.

In contrast to previous campaigns, the second stage of the campaign did not invoke a PowerShell command. Instead, it executed index.html using “mshta.exe,” a utility for executing Microsoft HTML Applications (HTAs). The step executed JavaScript and ActiveX code that created a new function with decoded ASCII data as its function body, among other operations.

The third and final stage leveraged that decoded ASCII data’s instructions to execute and download “index.dll” via regsvr32. In so doing, it installed Ursnif as the campaign’s final payload.

Ursnif’s Fork and Globetrotting Campaigns

Ursnif has been featured in several attack campaigns thus far in 2020. In January, for instance, researchers at FireEye detected malware that identified itself as “SaiGon version 3.50 rev 132.” A closer look revealed that this threat had based itself on the source code of Ursnif v3, suggesting a possible fork in the malware family’s development.

Just a few weeks later, SANS ISC unveiled its discovery of an attack campaign that relied on malspam to target German users with malware. Then, in March 2020, Cybaze-Yoroi Zlab intercepted a campaign in which attackers used a compromised Italian website to target Italian users with the Trojan.

How to Defend Against Malicious Macros

Security professionals can help defend their organizations against campaigns that use malicious macro code by relying on their security information and event management (SIEM) solution to detect malicious macro activity. Specifically, they should use the SIEM to detect the creation of new processes that could be spawned by malicious macros. Infosec personnel should also use tools like a VBA editor to extract and inspect macro code included in suspicious Office documents.

More from

Most organizations want security vendor consolidation

4 min read - Cybersecurity is complicated, to say the least. Maintaining a strong security posture goes far beyond knowing about attack groups and their devious TTPs. Merely understanding, coordinating and unifying security tools can be challenging.We quickly passed through the “not if, but when” stage of cyberattacks. Now, it’s commonplace for companies to have experienced multiple breaches. Today, cybersecurity has taken a seat in core business strategy discussions as the risks and costs have risen dramatically.For this reason, 75% of organizations seek to…

How IBM secures the U.S. Open

2 min read - More than 15 million tennis fans around the world visited the US Open app and website this year, checking scores, poring over statistics and watching highlights from hundreds of matches over the two weeks of the tournament. To help develop this world-class digital experience, IBM Consulting worked closely with the USTA, developing powerful generative AI models that transform tennis data into insights and original content. Using IBM watsonx, a next-generation AI and data platform, the team built and managed the entire…

How the FBI Fights Back Against Worldwide Cyberattacks

5 min read - In the worldwide battle against malicious cyberattacks, there is no organization more central to the fight than the Federal Bureau of Investigation (FBI). And recent years have proven that the bureau still has some surprises up its sleeve. In early May, the U.S. Department of Justice announced the conclusion of a U.S. government operation called MEDUSA. The operation disrupted a global peer-to-peer network of computers compromised by malware called Snake. Attributed to a unit of the Russian government Security Service,…

How NIST Cybersecurity Framework 2.0 Tackles Risk Management

4 min read - The NIST Cybersecurity Framework 2.0 (CSF) is moving into its final stages before its 2024 implementation. After the public discussion period to inform decisions for the framework closed in May, it’s time to learn more about what to expect from the changes to the guidelines. The updated CSF is being aligned with the Biden Administration’s National Cybersecurity Strategy, according to Cherilyn Pascoe, senior technology policy advisor with NIST, at the 2023 RSA Conference. This sets up the new CSF to…