FormBook | Threat Level: high | Type: Infostealer

Cryptographic Identifiers

SHA256b4a88d755d4ac88a380582ed5331b90b9c84872e6b6d04f773ffc08b4dbcf7c2
MD5eaee57ce6eb8a32b1851a5eefc5df546
File Typeexe
Size278.5 KB
First Seen2026-05-08
File Nameb4a88d755d4ac88a380582ed5331b90b9c84872e6b6d04f773ffc08b4dbcf7c2
Tagsexe, FormBook

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: b4a88d755d4ac88a380582ed5331b90b9c84872e6b6d04f773ffc08b4dbcf7c2
  • MD5: eaee57ce6eb8a32b1851a5eefc5df546

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: b4a88d755d4ac88a"
        threat_level = "high"
        first_seen = "2026-05-08"
    condition:
        hash.sha256(0, filesize) == "b4a88d755d4ac88a380582ed5331b90b9c84872e6b6d04f773ffc08b4dbcf7c2"
}

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 b4a88d755d4ac88a380582ed5331b90b9c84872e6b6d04f773ffc08b4dbcf7c2 # MD5 eaee57ce6eb8a32b1851a5eefc5df546
TypeValueNote
sha256 b4a88d755d4ac88a380582ed5331b90b9c84872e6b6d04f773ffc08b4dbcf7c2 Sample:FormBook
md5 eaee57ce6eb8a32b1851a5eefc5df546 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