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

Static analysis result for SHA-256 f99eba5258e4edb5…

MALICIOUS

Office (OLE) / .XLSX

1.33 MB
MD5: 3711af18827b3ae668721f177d928383 SHA-1: a5b2ec28978496fdb440840d361cdcd51392794d SHA-256: f99eba5258e4edb5004b76548e3566046a5374f9a71eab6f64b2afab3a7ba510
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204.002 Malicious File: User Execution: Malicious File T1559.001 Component Object Model Hijacking

The sample is an encrypted OOXML file that contains embedded OLE objects, specifically identified as Equation Editor objects. The presence of an 'Ole10Native' stream within the Equation Editor object, coupled with an anomaly in its header and size, strongly suggests it's being used as an exploit carrier. This points to a common technique for delivering malicious payloads via vulnerable components within Office documents.

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.