ZxxZDownloader — Office (OOXML) / .XLSX malware analysis

Static analysis result for SHA-256 bc03923e3cc28958…

MALICIOUS

Office (OOXML) / .XLSX

30.4 KB Created: 2006-09-16 00:00:00 UTC Authoring application: Microsoft Excel 12.0000 First seen: 2022-07-05
MD5: 1bf615946ad9ea7b5a282a8529641bf6 SHA-1: 358867f105b517624806c3315c5426803f7c42a7 SHA-256: bc03923e3cc2895893571068fd20dd0bc626764d06a009b91dac27982e40a085
180 Risk Score

Malware Insights

ZxxZDownloader · confidence 95%

MITRE ATT&CK
T1204 Malicious File Execution T1204.001 Malicious File Execution: User Execution

The critical ClamAV heuristic 'Ole2.Exploit.ZxxZDownloader-9944376-0' indicates the file is a known downloader exploiting the Equation Editor OLE object. This suggests the primary function is to fetch and execute a second-stage malicious payload. The embedded OLE object is the primary vector for this exploit.

Heuristics 4

  • Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR
    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.
  • ClamAV: Ole2.Exploit.ZxxZDownloader-9944376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Ole2.Exploit.ZxxZDownloader-9944376-0
  • ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV
    ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
  • Embedded OLE object medium OOXML_OLE_OBJECT
    Document contains an embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
ooxml_oleobject_00.bin
0c7158f9fc2093caf5ea1e34d8b8fffce0780ffd25191fac9c9b52c3208bc450		 ooxml-ole-object OOXML embedded OLE part: xl/embeddings/oleObject1.bin 6656 bytes
Detection
ClamAV: Ole2.Exploit.ZxxZDownloader-9944376-0
Obfuscation or payload: unlikely

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