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

Static analysis result for SHA-256 35886304fc88b40f…

MALICIOUS

Office (OLE) / .XLSX

1.22 MB
MD5: 90c0b7e9c1fd4bd0d54df507522cdf8b SHA-1: e650f713b7e88e87caac92cf7acfd873d598781b SHA-256: 35886304fc88b40fbaa83d1f2686d3870132a1d6154bc88cd5925a5c9b38b51c
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 a deliberate attempt to obscure its contents. It contains an Equation Editor OLE object, a common technique for embedding malicious content. The OLE object exhibits anomalies in its Ole10Native stream, suggesting it carries a payload designed to exploit vulnerabilities. The presence of multiple high-severity heuristics related to Equation Editor OLE objects strongly points to an exploit carrier.

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.