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Felismus is a Windows malware family associated with command-and-control communications, host profiling, and defense-evasion behavior. Observed samples collect basic victim information including the current username and local network IP address, then transmit that data to command-and-control infrastructure as part of victim identification and situational awareness. The malware has also been documented checking running processes associated with antivirus vendors, indicating security-software discovery intended to guide execution or reduce exposure to defensive tooling. Some samples use custom command-and-control traffic protection mechanisms, including Base64-based encoding and AES-based encryption with multiple keys, to obfuscate communications. Felismus has additionally masqueraded as legitimate Adobe-related files to blend into the host environment and has used command-line execution as part of its operation. The documented behavior supports characterization of Felismus as a backdoor-oriented implant focused on covert communications, host reconnaissance, and evasion on compromised Windows systems.
Mallory pivots from this family to the IOCs, detections, and named campaigns that touch your stack, and pages you when something new lands.
13 distinct techniques documented for this family, organized by ATT&CK tactic.
actors used the following command to rename one of their tools to a benign file name: ren "%temp%\upload" audiodg.exe ... APT1 ... used ... AcroRD32.exe ... as a name for malware ... APT28 ... changed extensions on files containing exfiltrated data to make them appear benign ... APT32 has renamed a NetCat binary to kb-10233.exe to masquerade as a Windows update.
AdFind can extract subnet information from Active Directory; actors used ipconfig /all after exploiting a machine; numerous malware and groups used ipconfig, ifconfig, arp, route, netsh, nbtstat, NBTscan, and related APIs to gather IP, MAC, DNS, DHCP, gateway, proxy, domain, ARP cache, routing, and adapter details.
The content repeatedly describes malware and threat actors collecting the victim username, identifying logged-in users, running whoami, query user, quser, or similar commands to determine the current user or user sessions.
The content repeatedly describes malware and threat actors collecting host details such as hostname, OS version, architecture, CPU, memory, BIOS, language, and other machine characteristics; e.g., "Action RAT has the ability to collect the hostname, OS version, and OS architecture of an infected host."
The content is a long ATT&CK-style listing showing numerous malware families and threat groups that 'use HTTP,' 'use HTTPS,' 'HTTP POST requests,' 'HTTP GET requests,' or 'HTTP/S' for command and control communications.
The content repeatedly describes malware and threat actors that can "download files from C2," "download additional payloads," "upload and download files," "retrieve payloads from the C2 server," and "copy files to remote machines."
ADVSTORESHELL C2 traffic is encrypted, then encoded with Base64 encoding. APT19 HTTP malware variant used Base64 to encode communications to the C2 server. APT33 has used base64 to encode command and control traffic.
The content is a catalog of malware and threat groups that encrypt command-and-control communications using algorithms such as DES, AES, RC4, XOR, Blowfish, RSA, Camellia, RC2, RC6, and custom ciphers.
"3PARA RAT command and control commands are encrypted within the HTTP C2 channel using the DES algorithm in CBC mode..."; "APT33 has used AES for encryption of command and control traffic."; "Carbanak encrypts the message body of HTTP traffic with RC2 (in CBC mode)."; "Duqu ... data stream can be encrypted with AES-CBC."; "PoisonIvy uses the Camellia cipher to encrypt communications."
26 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Backdoor that collects the current username and sends it to C2.
Collects victim LAN IP addresses and sends them to C2.
Collects the current username and sends it to C2.
Backdoor that collects the victim LAN IP address and sends it to C2.
Match every observed IP, domain, and hash against your live telemetry.
Named campaigns wielding this family, with evidence pinned to each claim.
CVEs this family uses for access and lateral movement.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Every documented technique, ranked by evidence weight.
Reddit, Mastodon, and CTI community discussion around this family.