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Jan 13, 2022
GootLoader Hackers Are Compromising Employees of Law and Accounting Firms, Warns eSentire
GootLoader Gang Launches Wide-Spread Cyberattacks Enticing Legal and Accounting Employees to Download Malware eSentire, the industry’s leading Managed Detection and Response (MDR) cybersecurity provider, is warning law and accounting firms of a wide-spread GootLoader hacker campaign. In the past three weeks and as recently as January 6, eSentire’s threat hunters have intercepted and shut down…
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Oct 28, 2021
Telarus and eSentire Expand Partnership to Safeguard Enterprises Globally Against Business Disrupting Ransomware and Zero-Day Attacks
London, UK and Sydney, Australia– Oct. 28, 2021 - eSentire, recognized globally as the Authority in Managed Detection and Response (MDR), today announces the expansion of its partnership with Telarus, the largest privately-held distributor of business cloud infrastructure and contact centre services. Building on their mutual success across North America, Telarus will bring eSentire’s Managed…
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Security advisories — Dec 15, 2021

Windows Zero-Day Vulnerability – CVE-2021-43890

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THE THREAT

In Microsoft’s December 14, 2021, Patch Tuesday vulnerability release, security patches were released for a high severity zero-day vulnerability impacting the Windows AppX installer. The vulnerability is tracked as CVE-2021-43890 (CVSS: 7.1). Exploitation allows a threat actor to create a malicious file that appears to be a legitimate application.

Exploitation in the wild has been observed in the delivery of multiple malware types including: Emotet, Trickbot, and BazarLoader. Organizations are strongly recommended to apply the relevant security patches as exploitation is ongoing.

What we’re doing about it

What you should do about it

Additional information

In an attack scenario, threat actors could craft a malicious attachment and deliver it to victims via either email or a link inside of an email; the attachment would appear as a legitimate application. Opening the malicious attachment leads to the deployment of malware. eSentire has detected attacks exploiting this technique. In observed attacks, the malicious attachment mimicked Adobe PDF Reader. An example of Emotet malware being delivered in this fashion is outlined in the December 2021 Threat Intelligence Observations On-Demand webinar.

As exploitation requires user interaction, it is critical that staff are trained in best security practices, especially surrounding email security.

References:

[1] https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-43890

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