Ongoing SonicWall Secure Mobile Access (SMA) Exploitation Campaign using the OVERSTEP Backdoor


Google Threat Intelligence Group (GTIG) has identified an ongoing campaign by a suspected financially-motivated threat actor we track as UNC6148, targeting fully patched end-of-life SonicWall Secure Mobile Access (SMA) 100 series appliances.

GTIG assesses with high confidence that UNC6148 is leveraging credentials and one-time password (OTP) seeds stolen during previous intrusions, allowing them to regain access even after organizations have applied security updates. Evidence for the initial infection vector was limited, as the actor’s malware is designed to selectively remove log entries, hindering forensic investigation; however, it is likely this was through the exploitation of known vulnerabilities.

Read more…
Source: Mandiant/GTG


Sign up for the Cyber Security Review Newsletter
The latest cyber security news and insights delivered right to your inbox


Related:

  • Tracking Iranian APT Screening Serpens’ 2026 Espionage Campaigns

    May 22, 2026

    Unit 42 researchers have observed evidence of cyberattacks by the Iran-nexus advanced persistent threat (APT) group Screening Serpens (aka UNC1549, Smoke Sandstorm and Iranian Dream Job). Based on Unite 42 visibility, researchers believe that the group targeted entities in the U.S., Israel and the United Arab Emirates, and likely two additional Middle Eastern entities. This research follows ...

  • Kali365 Phishing-as-a-Service Kit Hijacks Microsoft 365 Access Tokens

    May 21, 2026

    The Federal Bureau of Investigation (FBI) is issuing this Public Service Announcement (PSA) to warn the public about an emerging Phishing1-as-a-Service2 (PhaaS) platform called Kali365, first seen in April 2026. Kali365 has primarily been distributed via Telegram, enabling cyber threat actors to obtain Microsoft 365 access tokens and bypass multi-factor authentication3 (MFA) protocols without intercepting the user’s ...

  • Key Microsoft legacy tool is still being abused to launch malware campaigns

    May 21, 2026

    Cybercriminals are increasingly using a legitimate legacy Windows tool to deploy infostealers and loader malware, researchers are saying. A new Bitdefender report has claimed that since the start of 2026, there’s been an uptick in activity related to a Windows utility called Microsoft HTML Application Host (MSHTA), a legitimate utility that runs special HTML-based application files known as HTAs. Read more… Source:  ...

  • GitHub says internal repos exfiltrated after poisoned VS Code extension attack

    May 20, 2026

    GitHub, the world’s biggest code repository and DevOps platform, fell victim to a malicious Visual Studio Code (VS Code) extension. The company’s initial assessment is that only internal repositories were exfiltrated. The incident was reported by GitHub on X, with follow-up posts revealing a “poisoned VS Code extension” as the cause. The Microsoft-owned code shack continues to ...

  • Microsoft shuts down illegal code-signing operation used by ransomware criminals to mask their malware

    May 19, 2026

    Microsoft seized websites and took down hundreds of virtual machines running a cybercrime service that allegedly sold code-signing certificates to ransomware gangs, thus making their malware look like legitimate software – and allowing criminals to infect thousands of machines in the US, including at least 12 owned and operated by the Windows giant. Read more… Source: The ...

  • WantToCry ransomware remotely encrypts files

    May 19, 2026

    SophosLabs analysts investigated WantToCry ransomware attacks that involved the threat actors abusing the Server Message Block (SMB) service for initial access and then exfiltrating files to attacker-controlled infrastructure for remote encryption. The detection surface is significantly reduced because WantToCry operates without local malware execution, and there is no post-compromise activity beyond exfiltrating files and rewriting ...