Malvertising Campaign Leads to Execution of Oyster Backdoor


Rapid7 has observed a recent malvertising campaign that lures users into downloading malicious installers for popular software such as Google Chrome and Microsoft Teams.

The installers were being used to drop a backdoor identified as Oyster, aka Broomstick. Following execution of the backdoor, we have observed enumeration commands indicative of hands-on-keyboard activity as well as the deployment of additional payloads.

Read more…
Source: Rapid7


Sign up for our Newsletter


Related:

  • AI-Automated Threat Hunting Brings GhostPenguin Out of the Shadows

    December 8, 2025

    Hunting high-impact, advanced malware is a difficult task. It becomes even harder and more time-consuming when defenders focus on low-detection or zero-detection samples. Every day, a huge number of files are sent to platforms like VirusTotal, and the relevant ones often get lost in all that noise. Identifying malware with low or no detections is ...

  • Hook for Gold: Inside GoldFactory’s Сampaign That Turns Apps Into Goldmines

    December 3, 2025

    In February 2024, Group-IB uncovered sophisticated mobile threat campaigns that show how fast banking malware is evolving across the Asia-Pacific region. Ongoing monitoring of this evolving threat revealed a surge of aggressive mobile Trojans targeting both iOS and Android users, all operated by a single threat actor tracked as GoldFactory. Since releasing our initial report, we ...

  • Iranian hacker group deploys malicious Snake game to target Egyptian and Israeli critical infrastructure

    December 3, 2025

    An Iranian-aligned hacking group tracked as ‘MuddyWater’ has dramatically shifted tactics in attacks against Israeli and Egyptian critical infrastructure. Previous campaigns by the group, observed by ESET Research, were characteristically noisy in their tactics, techniques, and procedures (TTPs) making them easily detectable. However, the group has begun employing a new backdoor deployed via the Fooder loader, ...

  • Shai Hulud 2.0, now with a wiper flavor

    December 3, 2025

    In September, a new breed of malware distributed via compromised Node Package Manager (npm) packages made headlines. It was dubbed “Shai-Hulud”, and Kaspersky published an in-depth analysis of it in another post. Recently, a new version was discovered. Shai Hulud 2.0 is a type of two-stage worm-like malware that spreads by compromising npm tokens to republish ...

  • Tomiris wreaks Havoc: New tools and techniques of the APT group

    November 28, 2025

    While tracking the activities of the Tomiris threat actor, Kaspersky researchers identified new malicious operations that began in early 2025. These attacks targeted foreign ministries, intergovernmental organizations, and government entities, demonstrating a focus on high-value political and diplomatic infrastructure. In several cases, Kaspersky traced the threat actor’s actions from initial infection to the deployment of post-exploitation ...

  • New macOS malware chain could cause a major security headache

    November 26, 2025

    North Korean state-sponsored threat actors are targeting macOS users with new malware, utilizing a strategy that combines two popular approaches – fake job ads, and ClickFix, experts have warned. Security researchers Jamf confirmed they have spotted attacks in the wild using ClickFix, an attack method in which the victim is presented with a fake problem, and ...