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

Static analysis result for SHA-256 b2c99adc3072fb25…

MALICIOUS

Office (OOXML) / .XLSX

111.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000
MD5: 61aaa9ebd8e867834dce6bd1f19bf2a0 SHA-1: 82537fdf5484746e59b1ebcef4356f279def73c2 SHA-256: b2c99adc3072fb25b539070df0e6d3931a72b119a1ade1b0b423b9ee9c34438f
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.001 PowerShell T1059.003 Windows Command Shell T1566.002 Spearphishing Attachment

The sample is an Excel document containing a Workbook_Open macro that executes a batch file and a VBScript. The batch file appears to be responsible for downloading and executing a second-stage payload from multiple URLs. The VBScript is likely involved in the execution or staging of the payload. The ClamAV detection and the presence of VBA macros strongly indicate malicious intent.

Heuristics 6

  • ClamAV: Doc.Malware.Valyria-10004384-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Malware.Valyria-10004384-0
  • 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.
  • Workbook_Open macro high OLE_VBA_WBOPEN
    Workbook_Open macro
  • CreateObject call high OLE_VBA_CREATEOBJ
    CreateObject call
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains vbaProject.bin — VBA macros present

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
527d0656a0c2c323955d068683ef8f7e20c035cda247a1e24383595c0eb3403b
vba-macro oletools.olevba.extract_macros (decoded VBA source from OOXML) 7821 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.
vbaProject_00.bin
396ddbf0a73f0b7244e7c0e9d6516c4aaf723d78c03269a754bce8f960eb27d8
vba-project OOXML VBA project: xl/vbaProject.bin 37888 bytes
Detection
ClamAV: Doc.Malware.Valyria-10004384-0
Obfuscation or payload: likely
Carved macro source contains an auto-exec entry point and execution/download terms.