Cybersecurity Brief

Wednesday 21 May 2025

In this brief Cellcom, SK Telecom, RVTools, PowerSchool, KrebsOnSecurity, WordPress, +14 more
Vendors
Cellcom, SK Telecom, RVTools, PowerSchool, KrebsOnSecurity, WordPress, Virgin Media O2, AWS, Microsoft, Redis, Tenable, Yubico, Regeneron, VMware, 23andMe, Google
Threat actors
Hazy Hawk, Scattered Spider, SideWinder, VanHelsing

Major Incidents or Breaches

  • Cellcom Cyberattack: Wisconsin-based mobile carrier Cellcom confirmed a cyberattack caused widespread service outages beginning 14 May 2025.
  • SK Telecom Data Breach: SK Telecom disclosed a malware breach lasting three years (since 2022), exposing USIM data of 27 million subscribers.
  • RVTools Supply Chain Attack: The official website for RVTools, a VMware management utility, was compromised in a supply chain attack. Trojanized installers delivered the Bumblebee malware loader.
  • PowerSchool Extortion: A 19-year-old has pleaded guilty to a cyberattack on PowerSchool, involving extortion and exposure of student data.
  • KrebsOnSecurity DDoS Attack: KrebsOnSecurity experienced a near-record DDoS attack peaking at 6.3 Tbps.

Newly Discovered Vulnerabilities

  • WordPress ‘Motors’ Theme: A critical privilege escalation vulnerability allows unauthenticated attackers to take over admin accounts on sites using the premium Motors theme.
  • Virgin Media O2 Location Leak: A security flaw in Virgin Media O2’s mobile network could allow attackers to pinpoint call recipient locations within 100 square meters.
  • AWS Default IAM Roles: Researchers identified risky default IAM roles in AWS that can enable lateral movement and cross-service exploitation if misconfigured.

Notable Threat Actor Activity

  • Hazy Hawk: This group has been actively hijacking abandoned cloud resources (e.g., S3 buckets, Azure endpoints) via DNS misconfigurations and CNAME hijacking, targeting high-profile organizations including the US CDC, to deliver malware and conduct scams.
  • Scattered Spider: The group continues to target large retailers, shifting focus from UK to US organizations, leveraging IT help desk social engineering for initial access.
  • SideWinder APT: Targeted ministries in Sri Lanka, Bangladesh, and Pakistan using spear phishing, exploiting old Microsoft Office vulnerabilities, and deploying custom malware.
  • UnsolicitedBooker (China-aligned): Deployed the new MarsSnake backdoor in a multi-year campaign against a Saudi Arabian organization.
  • RedisRaider: A new Go-based cryptojacking campaign targets publicly accessible Redis servers to deploy XMRig miners.
  • VanHelsing Ransomware: The ransomware builder, affiliate panel, and data leak blog source code were leaked online, increasing the risk of further ransomware proliferation.
  • Fake Chrome Extensions: Over 100 malicious Chrome extensions have been discovered since February 2024, used to hijack browser sessions, steal credentials, and inject ads.
  • Service Desk Social Engineering: Attackers are increasingly targeting IT service desks with social engineering to bypass security controls (e.g., password resets, disabling MFA).
  • Novel Phishing Techniques: Recent phishing campaigns combine AES encryption with malicious npm packages to evade detection.
  • Supply Chain Threats: The RVTools incident highlights ongoing risks in software supply chains, with attackers distributing malware via compromised legitimate utilities.
  • Rise in Asia-based APTs: China and North Korea-aligned groups now account for over half of global APT attacks, with expanding international focus.
  • Exposure Management Enhancements: Tenable has added third-party connectors (AWS, Microsoft, competitors) to its platform for improved attack surface visibility.
  • Security Key Solutions: Yubico has expanded its YubiKey-as-a-Service globally, supporting hardware-based authentication in 175 countries.
  • AI Security Impacts: Increased adoption of AI agents is driving both new security opportunities and challenges, with most security leaders anticipating compliance and threat management implications.

Regulatory or Policy Developments

  • Genetic Data Privacy Concerns: Regeneron’s planned acquisition of 23andMe raises privacy concerns due to the lack of comprehensive federal regulation on genetic information transfers.