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

Static analysis result for SHA-256 3a6cc669542f5e3f…

MALICIOUS

Office (OLE) / .XLSX

1.30 MB
MD5: 05f49aa5b342dedd1d7b6673f3d8bc41 SHA-1: 9ca061b9851269f8b1d2fd990ebe119903a5f0fb SHA-256: 3a6cc669542f5e3f9a801e9344b182c71e72396e27afbeac14eeb3d3be0b9498
140 Risk Score

Malware Insights

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

The file is an encrypted Excel spreadsheet that utilizes embedded OLE objects, with a high-confidence detection of an Equation Editor OLE object. This strongly suggests an attempt to exploit the Equation Editor vulnerability (CVE-2017-11882) to deliver a payload. The presence of an 'Ole10Native' stream within the Equation Editor object indicates it carries a payload, likely a secondary stage. No document body text was extractable due to encryption.

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.