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

Static analysis result for SHA-256 dc7be4302f53818e…

MALICIOUS

Office (OLE) / .XLSX

1.21 MB
MD5: 1acc1b844a8ddd59fea4d31cca96f87f SHA-1: 6f3faa204be846cf1f28369e77aaa5ede3edd910 SHA-256: dc7be4302f53818ef222f07b6e16b006c8fb48455127c68b5fd1b9e24a882aa8
140 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Phishing: Spearphishing Attachment T1027 name own own own own own own own own own own own own own own own own own own own own own own own own own own own own own

The sample is a default-encrypted OOXML file containing an Equation Editor OLE object with a malformed Ole10Native stream, which is characteristic of CVE-2017-11882 and similar Equation Editor exploits. No scripts were extracted from this sample, but the structural anomalies in the embedded OLE object strongly indicate an exploit-based delivery mechanism for a second-stage 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.