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

Static analysis result for SHA-256 c7b3359bd20765b4…

MALICIOUS

Office (OLE) / .XLSX

1.14 MB
MD5: f181208fcc49c35d680dbd84b8b16685 SHA-1: f58c9ca172a0de269d27abddfd3161b4f29fc88f SHA-256: c7b3359bd20765b46a6482aa8b54635f722c783b635344923dc077446b7b41aa
140 Risk Score

Malware Insights

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

The sample is an OOXML file encrypted with a default password, indicating an attempt to hide its malicious contents. High-severity heuristics indicate the presence of an Equation Editor OLE object (T1566.001, T1204.002) which is known to carry malicious payloads. The OLE object contains an anomalous Ole10Native stream, suggesting it's designed to execute arbitrary code. No specific family could be identified, but the exploit carrier points to a common delivery method.

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.