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

Static analysis result for SHA-256 4bcf5d1e59dc4050…

MALICIOUS

Office (OLE) / .XLSX

1.14 MB
MD5: 1fd12c5baa5a8afe0e1ef88c9cc29dae SHA-1: d738ef6a5f2702dcc13beaeb2a405bbec3d862d3 SHA-256: 4bcf5d1e59dc40508bd83388ee1e5af5fca98dd59d91192ff27d4a5093ee9c2a
140 Risk Score

Malware Insights

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

The file is an encrypted OOXML document containing an embedded Equation Editor OLE object. This object exhibits anomalies suggesting it carries a malicious payload, likely exploiting a known vulnerability within the Equation Editor. The presence of multiple high-severity heuristics related to Equation Editor OLE objects strongly indicates this is the primary attack vector.

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.