Winsage
May 12, 2026
Researchers at Cyfirma have identified a cyberattack campaign named Operation SilentCanvas that targets Windows systems using deceptive JPEG files to infiltrate devices. The attack begins with victims receiving a file named sysupdate.jpeg, which contains a PowerShell script instead of an image. This script establishes staging environments and downloads additional malicious components while avoiding detection. The malware reconstructs command strings at runtime and downloads a secondary payload called access.jpeg, executed in memory. It exploits Microsoft's .NET compiler to create a custom launcher named uds.exe on infected machines. The malware takes control of a registry key to create a hidden desktop environment for undetected execution of malicious tools and installs a persistent Windows service, OneDriveServers, to maintain activity after reboots. Additionally, it can intercept usernames and passwords at the Windows login screen and create hidden local administrator accounts for long-term access. Security teams are advised to monitor the execution of commonly abused Windows binaries like csc.exe and ComputerDefaults.exe to mitigate risks.
