Malicious Office (OLE) / .XLSX — malware analysis report

Static analysis result for SHA-256 551b4ae768031815…

MALICIOUS

Office (OLE) / .XLSX

404.0 KB
MD5: 046eb7aa60d953bdee3923ddd6b72046 SHA-1: 1376a207074d555f19de93fc24e0a520b70eb4cf SHA-256: 551b4ae768031815c5d8732be0b4adb065942fc4361584e9625603b0c5377c65
120 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution

The critical heuristic firing indicates exploitation of CVE-2017-0199 via an OLE object, which is designed to act as a remote loader. The embedded object at 'xl/embeddings/oleObject1.bin' contains a URL pointing to a remote resource, strongly suggesting the document's purpose is to download and execute a second-stage payload. The OOXML is encrypted with a default password, a common technique to obscure malicious content.

Heuristics 3

  • 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.
    URL https://n9.cl/25qf
  • 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 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.