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

Static analysis result for SHA-256 265f1f9fa804f36e…

MALICIOUS

Office (OLE) / .XLSX

1.18 MB
MD5: ca10193ecf522d56001fccd8d7cd95a5 SHA-1: 3f0276f238ae3a08fe8fbde17036edab9f8b5e69 SHA-256: 265f1f9fa804f36e130200510d7130c5396aca52dd5352601dacf118e21a30dc
140 Risk Score

Malware Insights

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

The sample is an encrypted Excel file that utilizes a default password, a common technique to evade initial static analysis. It contains embedded OLE objects, specifically identified as Equation Editor objects, which are frequently used to deliver exploits. The presence of an anomalous Ole10Native stream within the Equation Editor object further suggests it's designed to carry a malicious 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.