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

Static analysis result for SHA-256 baac57b1f64f5d6e…

MALICIOUS

Office (OLE) / .XLSX

1.44 MB
MD5: c12a39b32626cd2b4ca80d41ffa7a24c SHA-1: 2105a2bc2161e9adfa0d3e087e43a466b9f5df58 SHA-256: baac57b1f64f5d6e9eeadc84424db056fe253119f0f1bf4b2f2b55f940bce4ab
180 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The file is an encrypted Excel spreadsheet containing an embedded Equation Editor OLE object. Heuristics indicate this object is anomalous and likely carries a payload, specifically targeting CVE-2018-0798. This suggests the document is designed to exploit the Equation Editor vulnerability upon opening to execute a malicious payload.

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.
  • CVE-2018-0798 — anomalous Equation Editor native stream high CVE likely CVE_2018_0798_EQUATION_NATIVE_ANOMALY
    Default-encrypted OOXML contains embedded Equation Editor data with anomalous native stream bytes consistent with a CVE-2018-0798-style exploit. This is treated as likely CVE evidence because the Equation object is malformed and payload-like.
  • 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.