Office (OLE) / .XLSX malware analysis — malicious · b01a0fff48021b37

MALICIOUS

Office (OLE) / .XLSX

31.3 KB First seen: 2022-06-28

MD5: ac39401c1d4c8cd7217e55916752ca90 SHA-1: 195333a12a2788640f1134fe30ff340e6c8286cd SHA-256: b01a0fff48021b37f8a790603f4043345a31487b13e33945207b1a915e66baa4

202 Risk Score

Malware Insights

MITRE ATT&CK

T1204.002 Malicious File T1566.001 Spearphishing Attachment

The file is an Office document encrypted with a default password, which is a common technique to hide malicious content. It exploits CVE-2017-0199 via an embedded OLE object to download a remote document from http://emulatoros.github.io@107.173.192.152/office_doc/document.doc. This indicates a downloader or dropper functionality, aiming to fetch and execute a second-stage payload.

Heuristics 6

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.
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://emulatoros.github.io@107.173.192.152/office_doc/document.doc

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