ZeffSec
Also known as Zeff Security
ZeffSec is a hacktivist collective focused on infrastructure-level disruption and exposing vulnerabilities in centralized digital networks. In March 2026, the group claimed responsibility for a large-scale DDoS attack against ArvanCloud, Iran's primary cloud and CDN provider, causing widespread service outages across platforms including the online education service Skyroom. The group announced the operation via Telegram, stating their goal was disruption of centralized infrastructure rather than data theft.
CVEs in recent coverage
No CVEs named alongside this actor in the last 90 days.
Recent victims
No leak-site posts on record for this group.
Recent activity
No posts or advisories have named this actor recently.
References
From the MISP threat-actor galaxy, MITRE ATT&CK and RansomLook (CC BY 4.0). Activity is any post or advisory Watch Floor collected that names the actor or one of its aliases.