Formbook Office (OLE) / .XLSX malware analysis — malicious · 1a6bd6c151c3fde7

MALICIOUS

Office (OLE) / .XLSX

150.6 KB First seen: 2022-07-08

MD5: 0d249bd4508af9ebd1c952bf4c8e9e40 SHA-1: 6ceb5fe20d9668dca48465718376842a083cc3ab SHA-256: 1a6bd6c151c3fde737823d08a8fb5e3dd99de1bc505cfb28673c5e3eaf066f98

262 Risk Score

Malware Insights

Formbook · confidence 95%

MITRE ATT&CK

T1204 Malicious Link T1204.001 Malicious Link: Malicious Link T1059 Command and Scripting Interpreter T1071 Application Layer Protocol T1071.001 Application Layer Protocol: Web Protocols

The sample is a password-encrypted OOXML file identified as a carrier for exploit code. It leverages CVE-2017-0199 via an OLE object to fetch a remote document from the URL http://www.javatpoint.com@3236145346/swift_copy/inv14/receipt.doc. ClamAV detection confirms it as a Formbook downloader, indicating the likely intent to download and execute a second-stage payload.

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/inv14/receipt.doc

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