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

Static analysis result for SHA-256 dbd2b66797260a82…

MALICIOUS

Office (OLE) / .XLSX

1.33 MB
MD5: 6052fc6db72cea9c871f421ab2b6b529 SHA-1: 4543afa284e286f4fe5fc3952feeddb42de92e6a SHA-256: dbd2b66797260a826db05cf6f7025687a86c5dcdc2447bacbae058b1244d532b
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 an Equation Editor OLE object. This object is known to be used as an exploit carrier, specifically for vulnerabilities like CVE-2017-11882. The high-entropy Ole10Native stream within the Equation Editor object suggests it contains a malicious payload. The file is likely delivered as an attachment, prompting the user to open it and trigger the exploit.

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.