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

Static analysis result for SHA-256 aa0b6779d2486f01…

MALICIOUS

Office (OLE) / .XLSX

1.28 MB
MD5: 0dbca26e2986e05613c77dc03d534ae6 SHA-1: 6f50819132f9bb8fba1ff4553708138eb67d4995 SHA-256: aa0b6779d2486f010c5ae03fcc7949dd6d4bc5051a2c6e9a1f88ab986e4116e5
140 Risk Score

Malware Insights

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

The sample is an encrypted OOXML file that utilizes a default password, indicating an attempt to obscure its malicious contents. High-severity heuristics identify it as an exploit carrier, specifically containing an Equation Editor OLE object. This object appears to carry a payload within its Ole10Native stream, a known technique for exploiting vulnerabilities like CVE-2017-11882. The presence of embedded OLE objects and the exploitation of the Equation Editor strongly suggest a malicious intent to deliver a secondary payload.

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.