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

Static analysis result for SHA-256 40592c189cf49a92…

MALICIOUS

Office (OLE) / .XLSX

1.32 MB
MD5: 9788b072919af6edda97adafe8d74853 SHA-1: 93debcf7db0bb179a57403b1158c03979759071e SHA-256: 40592c189cf49a920e587da749405147fa73d4f415c92333f837f3d8ed32fcf6
160 Risk Score

Malware Insights

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

The sample is a password-encrypted Office XLSX file. High-severity heuristics indicate it contains an Equation Editor OLE object (CLSID offset 0x450) which is anomalous and carries a payload-like Ole10Native stream. This strongly suggests exploitation of a vulnerability within the Equation Editor component, likely CVE-2017-11882, to execute arbitrary code. No scripts were extracted, but the presence of the embedded OLE object points to a classic exploit carrier.

Heuristics 5

  • 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 document is password-encrypted medium OFFICE_ENCRYPTED_PACKAGE
    OLE container holds MS-OFFCRYPTO encrypted package (Standard Encryption (Office 2007+, AES-128)).
  • 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.

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