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

Static analysis result for SHA-256 d24978a012cbc84e…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: 7e1ec8f3616fe0949dd8a39d6b75e2b4 SHA-1: 469543d68265d4e30073964eddbc30abe742614a SHA-256: d24978a012cbc84ebbf5ce58e14fa68d9fed71d72db1fea09b23a521d0c75707
200 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious File T1566 Phishing T1204.002 Malicious File: User Execution

The file is an Excel spreadsheet that is encrypted with a default password and contains an embedded Equation Editor OLE object. This object carries a payload-like Ole10Native stream, indicating it is likely used to exploit a vulnerability and deliver a second-stage payload. ClamAV detection confirms this is a downloader.

Heuristics 5

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    Default-encrypted OOXML embedded OLE object xl/embeddings/oleObject1.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
  • ClamAV: Xls.Downloader.af2fa5c5d0587870-9978799-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Downloader.af2fa5c5d0587870-9978799-0
  • 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.
  • Equation Editor object carries payload-like Ole10Native stream high OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY
    Default-encrypted OOXML embedded OLE object declares the Equation Editor CLSID but stores a large high-entropy Ole10Native stream with malformed package sizing. This is exploit-shaped Equation/OLE payload evidence.
  • 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.