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

Static analysis result for SHA-256 b21f8f25e274da77…

MALICIOUS

Office (OLE) / .XLSX

1.17 MB
MD5: fb4920dc4cf94d6ae15ca6edd202f790 SHA-1: 41988b5fade9950bb630e5b082467b24cb944c1a SHA-256: b21f8f25e274da771bdbe525c43aada072dea06b902e9b1080e6156006379f52
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The file is an OOXML document that is encrypted with a default password and contains embedded OLE objects, specifically identified as Microsoft Equation Editor. This strongly suggests it's an exploit carrier designed to leverage a vulnerability within the Equation Editor to execute a payload. The presence of an 'Ole10Native' stream anomaly within the Equation Editor object further supports this, indicating a potential payload delivery mechanism.

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.