Threats tagged 'brute-force'

During Q3 2026, attacks targeting poorly managed Linux SSH servers were observed, primarily using brute force and dictionary attacks. The main malware families involved were ShellBot, a Perl-based DDoS bot, and Fisieredoor, a backdoor capable of command execution and deploying SSH dictionary attack tools. Attackers used wget or curl to download malware, then installed user-mode rootkits, process masking tools (XHide), and XMRig cryptocurrency miners. The malware launcher used ld.so.preload to inject rootkits and disguised mining processes as legitimate bash sessions. Fisieredoor also deployed tools for credential harvesting and lateral movement, transmitting successful authentication data to command servers.

A significant spike in brute-force traffic targeting Fortinet SSL VPNs was observed on August 3, with over 780 unique IPs triggering the Fortinet SSL VPN Bruteforcer tag. The activity was deliberate and precise, focusing on FortiOS. Two distinct waves of attacks were identified: a long-running set of brute-force activity and a sudden burst beginning August 5. The second wave shifted from targeting FortiOS to FortiManager - FGFM profile. Historical data revealed a potential residential origin or proxy use. The analysis suggests evolving attack patterns and potential reuse of tooling. Research indicates that such spikes often precede new vulnerability disclosures within six weeks. Defenders are advised to use GreyNoise to search for and block malicious IPs associated with this campaign.

Campaign#fortios#ip blockingGermany+6

The Efimer Trojan is spreading through compromised WordPress sites, malicious torrents, and email campaigns impersonating lawyers. It steals cryptocurrency by replacing wallet addresses in the clipboard and can execute additional malicious scripts. The Trojan communicates with its command-and-control server via the Tor network. It has additional capabilities to brute-force WordPress sites and harvest email addresses for further distribution. The malware primarily targeted users in Brazil, India, Spain, Russia, Italy, and Germany between October 2024 and July 2025, affecting over 5,000 Kaspersky users.

Malware#wordpress#torrentGermany+5