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

Static analysis result for SHA-256 bca0d3153e84daba…

MALICIOUS

Office (OLE) / .XLSX

1.16 MB
MD5: ad388bd732c0149e39768a941a029dc9 SHA-1: af4d97617d1f1389cdb8d6abd555c55759da5eb9 SHA-256: bca0d3153e84daba729309a5fec39def6bd120c9e6e3d84619803e57e57f2fdf
200 Risk Score

Malware Insights

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

The file is an OOXML spreadsheet encrypted with a default password, indicating it's likely an exploit carrier. It contains an Equation Editor OLE object with an anomalous Ole10Native stream, a known technique for delivering malicious payloads. ClamAV also detected it as a downloader. The combination of these factors strongly suggests an exploit delivery mechanism targeting the Equation Editor vulnerability.

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.