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

Static analysis result for SHA-256 ef1ba755cce93593…

MALICIOUS

Office (OOXML) / .XLSX

111.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000
MD5: 50f64507116d7eba3b50eab0058467fa SHA-1: c6e1631a0dd6642594a3032ec171567ea252d5a6 SHA-256: ef1ba755cce935932bf6c9eb07b1e625814982ffb5c2d1c51fe6cf76e2dd20a9
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File

The file is an Excel macro-enabled document with a Workbook_Open macro that executes a series of commands. The script attempts to download and execute a second-stage payload from multiple URLs, including 'http://reumatismclinic.com/-//scCn3mbJRpsBaKBbrC/'. It also creates a batch file at 'c:\programdata\jledshf.bat' and a VBScript at 'c:\programdata\sduoixo.vbs' for execution. The ClamAV detection 'Doc.Malware.Valyria-10004384-0' further confirms its malicious nature.

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
77eed67b9d1ab0e356096e7d4a2ce9ba30d93260296c797cb41a3ac258df5bf8
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.