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

Static analysis result for SHA-256 d40de7ba15f0ec97…

MALICIOUS

Office (OLE) / .XLSX

1.39 MB
MD5: f886a27269a2648e3cb5cf4ce85d579b SHA-1: 57d8a5458723e446f7cdab9b511f4970dd581ded SHA-256: d40de7ba15f0ec97bd08e16c2c8ea5c73f224e35c0ddf4d0599d0e7ea0640ae0
140 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an encrypted OOXML file containing an Equation Editor OLE object, a known carrier for exploits. The 'OLE_EQUATION_OLE10NATIVE_PAYLOAD_ANOMALY' heuristic indicates that this object likely contains a malicious payload. The file's structure and the presence of the Equation Editor exploit suggest it's designed to execute arbitrary code upon opening, likely as a downloader for further malicious activity.

Heuristics 4

  • 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.
  • 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.