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

Static analysis result for SHA-256 ad89a549970d09f9…

MALICIOUS

Office (OLE) / .XLSX

1.18 MB
MD5: 00d50ac2be4e6bb4c85e34d2a667c9e8 SHA-1: 9aae58e353db4915a01022c80e44416e37c21270 SHA-256: ad89a549970d09f980f5da83ec8d6c2970093c38d3b615c19b21e6247fc73547
200 Risk Score

Malware Insights

MITRE ATT&CK
T1566.002 Spearphishing Attachment T1204.002 Malicious File

The file is an encrypted Excel spreadsheet that utilizes an embedded Equation Editor OLE object, a known technique for delivering malicious payloads. The presence of an 'Ole10Native' stream anomaly within the Equation Editor object strongly suggests it carries a payload. ClamAV detection as 'Xls.Downloader' further supports its malicious nature as a downloader. The exact payload and delivery mechanism are not fully discernible from the provided static analysis, hence the unknown family.

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.

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