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

Static analysis result for SHA-256 0a59f5d78b6b0300…

MALICIOUS

Office (OOXML) / .XLSX

111.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000
MD5: 6f892bec8596ec608ffdad829345bbd1 SHA-1: 294a7d8411724359fa3c9abbeef81e2e07ca4073 SHA-256: 0a59f5d78b6b030003722a31f673109fe4b763658e45fce0db6e3a287419dbd4
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1566.001 Spearphishing Attachment

The sample contains a Workbook_Open VBA macro that executes obfuscated commands. These commands attempt to download and execute payloads from multiple URLs, including 'http://reumatismclinic.com/--/scCnm3mbJRpwBsKBbrC/'. The macro also creates batch and VBScript files in 'c:\programdata\' and attempts to execute a PowerShell command with encoded arguments, indicating a downloader or droppper functionality.

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
  • VBA p-code auto-exec with execution tokens high OLE_VBA_PCODE_AUTOEXEC_EXEC
    Compiled VBA/cache stream contains an auto-execution token together with shell/download/object-execution tokens. This catches p-code-only or source-extraction-failure macro documents where visible source is unavailable.
  • VBA project inside OOXML medium OOXML_VBA
    Document contains a VBA project — 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
vbaProject_00.bin
182d80c7b3412fc517788a923eb1422e0ae705eed23989cffb4fe2c6007dfeb8		 vba-project OOXML VBA project: xl/vbaProject.bin 37888 bytes
Detection
ClamAV: Doc.Malware.Valyria-10004384-0
Obfuscation or payload: unlikely

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