Office (OLE) / .XLSX malware analysis — malicious · cc15d2c75560b35d

MALICIOUS

Office (OLE) / .XLSX

28.0 KB First seen: 2022-07-27

MD5: 0e008d811aadb9296b9f0a693a93a649 SHA-1: 5d99468e4561bc821fb4f9e4b64e312a488a89f7 SHA-256: cc15d2c75560b35d8f8f6a454f320a18f8e7a9d64166bf1f109c102310286cbd

142 Risk Score

Malware Insights

MITRE ATT&CK

T1204 Malicious Link T1204.001 Malicious Link: Embedded Link T1059 Command and Scripting Interpreter T1059.001 Command and Scripting Interpreter: PowerShell T1566 Phishing T1566.001 Phishing: Spearphishing Attachment T1566.002 Phishing: Spearphishing Link

The sample is an encrypted Office document that exploits CVE-2017-0199 via an OLE2Link object. It attempts to download a secondary document from the URL http://23.95.52.140/msoffice/doc5/doc5.docx, which is likely a further stage of the attack. The encryption and exploit carrier heuristics indicate a deliberate attempt to conceal malicious content.

Heuristics 5

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.
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://23.95.52.140/msoffice/doc5/doc5.docx

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