VU#718077: UEFI Shell module embedded in SPI Flash can be used to bypass Secure Boot
CERT/CC details VU#718077: UEFI Shell embedded in SPI flash lets attackers bypass Secure Boot and execute pre-boot code; patches issued.
CERT/CC's VU#718077, reported by Eclypsium researcher Stas Lyakhov, describes how a UEFI Shell embedded in SPI flash can be abused by attackers who can modify UEFI boot configuration, creating multiple boot entries that bypass controls preventing the Shell from launching under Secure Boot. The Shell's dmem and mm commands allow arbitrary physical memory read/write, letting attackers overwrite Secure Boot values and execute unauthorized pre-boot code that can persist across reboots and OS reinstalls while degrading EDR effectiveness. AMI confirmed its Aptio UEFI BDS module is affected (CVE-2026-33197), and Cisco published an advisory for a variation affecting UCS Servers and UCS-based appliances (CVE-2026-20293). Firmware patches are being rolled out through OEM and IBV BIOS build pipelines.
Hackers Use ClickFix Lures to Deploy MacSync Stealer and Bypass macOS Security.
ClickFix malvertising campaigns deliver MacSync, a macOS infostealer sold as MaaS that bypasses Gatekeeper via Terminal commands and steals credentials.
Threat actors use ClickFix social-engineering lures, SEO poisoning, and malvertising impersonating brands like Claude, ChatGPT, Zoom, and Docker to trick users into pasting curl-to-zsh commands into Terminal, evading Gatekeeper and notarization checks. The MacSync Stealer (formerly Mac.c, emerged April 2025, linked to developer 'Mentalpositive') is a 64-bit Mach-O stager with single-byte XOR string obfuscation that daemonizes, polls C2 with custom API-key headers, streams AppleScript payloads into osascript, and persists via fake LaunchAgents. It steals browser credentials, Keychain data, SSH keys, session tokens, and crypto wallets, exfiltrating archives in 10MB HTTP PUT chunks. Microsoft documented more than 30 related MacSync domains.
WordlistLoader Delivers Amatera via ClickFix, SynkLoader Phishes Windows Passwords
Gen Digital details WordlistLoader delivering Amatera Stealer via ClickFix and EtherHiding, while SynkLoader phishes Windows credentials through Microsoft Teams.
Gen Digital identified WordlistLoader, an intermediate stage that reconstructs shellcode encoded as plain English words (or 16-byte UUID chunks) and loads Amatera Stealer 4.3.3-alpha1, delivered through ClearFake ClickFix prompts on compromised websites. The chain uses EtherHiding to fetch JavaScript from a blockchain smart contract, hidden cmd.exe via conhost, WebDAV-mounted shares with rundll32 execution, and ETW bypass via hardware breakpoints. The stealer adds hardened WoW64 syscalls, Heaven's Gate indirect-syscall trampolines and a redesigned application-bound encryption bypass. Separately, Expel observed SynkLoader distributed via Microsoft Teams phishing impersonating IT service desks, installing an MSI from Azure blob storage and serving a fake lock screen to capture credentials.