FormBook | Threat Level: high | Type: Infostealer

Cryptographic Identifiers

SHA256b9049cad3dc773d0b4ab4b1526e560060d44c668de2d90ad8884ca7b018d8237
MD5959656cb9605cec3d3a6071e8451a891
File Typexls
Size931.5 KB
First Seen2026-05-15
File NameInvoice.xls
TagsFormBook, xls

Malware Family: FormBook

FormBook, MaaS stealer'dır.

TypeInfostealer
Programming LanguageC
Target PlatformWindows
C2 ProtocolHTTP
PurposeForm verisi hırsızlığı
First Seen Year2016
AliasesxLoader

Threat Indicators (IOC)

  • SHA256: b9049cad3dc773d0b4ab4b1526e560060d44c668de2d90ad8884ca7b018d8237
  • MD5: 959656cb9605cec3d3a6071e8451a891

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: b9049cad3dc773d0"
        threat_level = "high"
        first_seen = "2026-05-15"
    condition:
        hash.sha256(0, filesize) == "b9049cad3dc773d0b4ab4b1526e560060d44c668de2d90ad8884ca7b018d8237"
}

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 b9049cad3dc773d0b4ab4b1526e560060d44c668de2d90ad8884ca7b018d8237 # MD5 959656cb9605cec3d3a6071e8451a891
TypeValueNote
sha256 b9049cad3dc773d0b4ab4b1526e560060d44c668de2d90ad8884ca7b018d8237 Sample:FormBook
md5 959656cb9605cec3d3a6071e8451a891 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