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

Static analysis result for SHA-256 90762be7a841f1f0…

MALICIOUS

Office (OLE) / .XLSX

993.5 KB
MD5: f38a2d79db1f13bef03cf23b1e296c27 SHA-1: 3e5028f6242549931dbb5675f412d7cd02a4297e SHA-256: 90762be7a841f1f0830a3ddddee2bb85c60d4d2662f0fb81263fce53d15aca87
140 Risk Score

Malware Insights

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

The file is an encrypted OOXML document that contains embedded OLE objects, specifically identified as an Equation Editor exploit carrier. The presence of an 'Ole10Native' stream within the Equation Editor object, with an anomalous header and a significantly smaller stream size than declared, strongly suggests it's designed to deliver a secondary payload. The encryption with a default password further indicates an attempt to obscure the malicious content.

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.