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

Static analysis result for SHA-256 2d7a8e7a0f67a0a1…

MALICIOUS

Office (OOXML) / .XLSX

111.6 KB Created: 2015-06-05 18:17:20 UTC Authoring application: Microsoft Excel 12.0000
MD5: 1ccbbb51cf235f6b5d1617bb7abb1e4b SHA-1: dcea1d4d8f49d762a1b92f0326fd700e07acc028 SHA-256: 2d7a8e7a0f67a0a1199a93398657687233c322b90b257b4390599f5b426c0a6d
260 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1204.002 Malicious File T1140 Deobfuscate or Obfuscate

The sample is an Excel document containing a Workbook_Open macro that executes a series of commands. The macro attempts to create a batch file at 'c:\programdata\jledshf.bat' and a VBScript file at 'c:\programdata\sduoixo.vbs'. The VBScript file is constructed using string concatenation and appears to download payloads from multiple URLs, including 'http://reumatismclinic.com/./scCn3mbJRPsBKBrc/'. The presence of ClamAV detections and the macro's behavior strongly indicate a malicious downloader.

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
4f98702fe608dff93e9d82422163b6636ad93ca93bb971d312654f28b859be5c
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.