Formbook — Office (OLE) / .XLSX malware analysis

Static analysis result for SHA-256 19805fff1a0a92c8…

MALICIOUS

Office (OLE) / .XLSX

150.5 KB First seen: 2022-07-08
MD5: e091517b53c73d9f5ca61a8d00c381d3 SHA-1: 89091eb62aebc1bd97a8a1615bb77aa2381e77bd SHA-256: 19805fff1a0a92c8b01f54bdf41d8f843487f06af75502ffbff4bf2c18c098b2
262 Risk Score

Malware Insights

Formbook · confidence 95%

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is a password-encrypted Office document that exploits CVE-2017-0199 via an embedded OLE object. This exploit is designed to download and execute a remote document from the URL http://www.javatpoint.com@3236145346/swift_copy/inv18/receipt.doc. ClamAV detection further identifies the sample as Doc.Downloader.Formbook, indicating its role as a downloader for the Formbook banking trojan.

Heuristics 7

  • OLE2Link / URL Moniker → remote loader — CVE-2017-0199 critical CVE likely CVE_2017_0199
    Document contains an embedded OLE link object whose URL Moniker points to a remote URL. When the host file is opened, Office follows the link, downloads the URL, and processes the response based on its Content-Type (HTA -> mshta.exe, RTF → Word, etc.) — the documented CVE-2017-0199 primitive. The URL extension is not a reliable filter; servers can return different payloads to Office's user agent.
  • Encrypted Office package with CFB FAT corruption critical OLE_ENCRYPTED_AND_MALFORMED
    Encrypted-package shape co-occurs with FAT-chain corruption — the documented combined evasion form.
  • ClamAV: Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Downloader.Formbook-bc97c1e0c33c3c93-9951465-0
  • Default-encrypted OOXML exploit carrier layout high OOXML_ENCRYPTED_EXPLOIT_CARRIER_SHAPE
    Default-password encrypted OOXML package contains embedded OLE object parts and additional activation/decoy parts. This layout is common in malicious Excel exploit delivery and requires inspecting the decrypted package.
  • Office document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007, AES)).
  • Office OOXML encrypted with default VelvetSweatshop password medium OFFICE_DEFAULT_PASSWORD_ENCRYPTED_OOXML
    OLE EncryptedPackage decrypts with Excel's built-in VelvetSweatshop password. Office opens this transparently, and malware uses it to hide OOXML exploit parts from scanners that only inspect the outer OLE container.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.javatpoint.com@3236145346/swift_copy/inv18/receipt.doc