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

Static analysis result for SHA-256 c638b5c44c093763…

MALICIOUS

Office (OLE) / .XLSX

1.19 MB
MD5: c9c4814f83a4ad4d24a9c0732391cb5a SHA-1: d5bd78db13fdb8452e052a3bb95b53c5f04029ee SHA-256: c638b5c44c093763cda5321940b93904e6a781b4aa656785c580b2767b0b2eb3
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1559.001 Component Object Model

The sample is an encrypted OOXML file that contains an Equation Editor OLE object. This object exhibits anomalies suggesting it carries a payload, likely exploiting a vulnerability within the Equation Editor component to achieve arbitrary code execution. The default encryption and the presence of embedded OLE objects strongly indicate a malicious intent to exploit this known 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.