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

Static analysis result for SHA-256 b4621b74fade93a4…

MALICIOUS

Office (OLE) / .XLSX

1.23 MB
MD5: 5f8fa6e46302b11f6934954df848a20f SHA-1: 6e4903c2f690fbc8d3f0f7e32bb5e7678a880329 SHA-256: b4621b74fade93a4102c8912a08e47b44ec60bc69017aacab084d8982097d7c8
140 Risk Score

Malware Insights

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

The file is an encrypted OOXML document identified as an exploit carrier. High-severity heuristics indicate the presence of an Equation Editor OLE object containing a payload-like Ole10Native stream. This strongly suggests the document is designed to exploit a vulnerability within the Equation Editor to execute a secondary payload.

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.