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

Static analysis result for SHA-256 1b8ee3f3c63ded6c…

MALICIOUS

Office (OLE) / .XLSX

1.25 MB
MD5: 3c3847097e98abe71f24aaf91e6953d8 SHA-1: 94038441d4abc9856da1f77eada774759ad32bec SHA-256: 1b8ee3f3c63ded6c6bc4b1fb54804282038c8df4eb41a460b8b17f526a34f52d
140 Risk Score

Malware Insights

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

The sample is an encrypted Office XLSX file that contains embedded OLE objects, specifically identified as Equation Editor objects. These objects are known exploit carriers. The presence of an 'Ole10Native' stream within the Equation Editor object, coupled with an anomalous header and size discrepancy, strongly suggests it's designed to deliver a malicious payload. The default encryption further indicates an attempt to obscure the malicious content.

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.