FormBook | Threat Level: high | Type: Infostealer

Cryptographic Identifiers

SHA2561c0a398026a91a03b059ff55bb6743b2bc76903da0c83016cee9520851618109
MD53244958b2acfc178b7151ba0e8572008
File Typejs
Size3145.4 KB
First Seen2026-05-28
File Name900882783782782.JS
TagsFormBook, js

Malware Family: FormBook

FormBook, MaaS infostealer'dır.

TypeInfostealer
Programming LanguageC
Target PlatformWindows
C2 ProtocolHTTP
PurposeForm verisi, tuş kaydı
First Seen Year2016
AliasesxLoader

Threat Indicators (IOC)

  • SHA256: 1c0a398026a91a03b059ff55bb6743b2bc76903da0c83016cee9520851618109
  • MD5: 3244958b2acfc178b7151ba0e8572008

You can verify all hash values of this sample on VirusTotal.

System Cleanup Guide

  1. Disconnect the system from the network immediately
  2. Yeni bir cihazdan banka hesabı, sosyal medya ve e-posta şifrelerini değiştirin
  3. Move crypto wallets to a new address and abandon the old ones
  4. Start a full scan with up-to-date antivirus
  5. Clear saved browser passwords and enable 2FA
  6. Sign out of all sessions on every affected service

YARA Rule Hints

rule FormBook_SHA256 {
    meta:
        description = "FormBook sample: 1c0a398026a91a03"
        threat_level = "high"
        first_seen = "2026-05-28"
    condition:
        hash.sha256(0, filesize) == "1c0a398026a91a03b059ff55bb6743b2bc76903da0c83016cee9520851618109"
}

FormBook — Malware Profile

FormBook web form verisi ve credential hırsızı. SmartAssembly paketleyici. İspanyolca LATAM elektrik faturası lür.

Malware Type
Infostealer
Programming Language
C
C2 Protocol
HTTP
Target Systems
Windows
Also Known As (AKA)
xLoader

Technical Details

C dili, Windows API hooking (form grabbing), HTTP POST C2, browser form stealer, keylogger, screenshot, clipboard monitor, process injection (process hollowing)

Attribution / Threat Actor

ABD'de gelistirilmis; satis darknet forumlari uzerinden yapilmis. Dunya genelindeki multuple suc gruplarina hizmet veren MaaS platformu.

Capabilities & Behavior

Tarayıcı Kimlik Bilgileri
Çerez Hırsızlığı
Kripto Cüzdan Çalma
Sistem Bilgisi
Ekran Görüntüsü
FTP/SSH İstemci Şifreleri
E-posta İstemcisi Çalma
Veri Sızıntısı

IOC List (2 indicators)

IOC — FormBook
# SHA256 1c0a398026a91a03b059ff55bb6743b2bc76903da0c83016cee9520851618109 # MD5 3244958b2acfc178b7151ba0e8572008
TypeValueNote
sha256 1c0a398026a91a03b059ff55bb6743b2bc76903da0c83016cee9520851618109 Sample:FormBook
md5 3244958b2acfc178b7151ba0e8572008 Sample:FormBook

C2 Servers (5 recorded servers for this family)

Address Type Port Protocol Status Country
45.61.136.16 ip 80 HTTP active US
hxxp://freeupgrades.net/s1xt/ domain 80 HTTP inactive US
103.75.160.239 ip 443 HTTPS inactive HK
3.29.19.86 ip — TCP inactive —
form-book.club domain 80 HTTP sinkholed —

C2 addresses are provided only from malware samples manually verified by the KEYDAL team. Commercial use is prohibited.

Tags
formbookinfostealermalwarehighsha256hash-analizi