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

Static analysis result for SHA-256 2c1f9a272ab0b4f9…

MALICIOUS

Office (OLE) / .XLSX

1.20 MB
MD5: 52ea97b7d1ba5f55516650c37680136f SHA-1: 6e42c85fa3e745cd613d10d77960ae05c8f288dd SHA-256: 2c1f9a272ab0b4f9f297a5e76fb25a64f7e7f95e0e92e62846061b47e061cdb7
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that contains embedded OLE objects, specifically identified as an Equation Editor exploit carrier. The presence of an Equation Editor OLE object with a payload-like Ole10Native stream strongly suggests it's designed to exploit a known vulnerability, likely CVE-2017-11882, to execute a secondary payload. The encryption with a default password further indicates an attempt to evade static analysis.

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.