Malicious Office (OLE) / .XLS — malware analysis report

Static analysis result for SHA-256 7a1ba08cd168e5f5…

MALICIOUS

Office (OLE) / .XLS

154.0 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel
MD5: 856ce291b91c96ff9f1dc40406e6c798 SHA-1: b97f3ff8d37418993e391dce209345eea0c2ff8b SHA-256: 7a1ba08cd168e5f59ad9cc8ad300457088c3da5ed87b51befe9e2c80e5d96a39
360 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The critical heuristics indicate the presence of a Workbook_Open VBA macro that utilizes WScript.Shell to download and execute a second-stage payload. The obfuscated VBA code, while difficult to fully deobfuscate, clearly aims to achieve this malicious objective. The use of Shell() and WScript.Shell are key indicators of this behavior.

Heuristics 8

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • VBA downloads and writes a file to disk critical OLE_VBA_HTTP_DROP_EXEC
    VBA reads an HTTP response body and writes it to disk (ADODB.Stream SaveToFile). Combined with the auto-exec/Shell paths this is a download-drop dropper even when the COM ProgIDs are built dynamically to evade keyword scanning.
  • Reference to Windows Script Host high SC_STR_WSCRIPT
    Reference to Windows Script Host
  • 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
64263ecdb3aa307bc5207c4c5f407e558197242bf81d25d63b1bfbb3b4b4a83d		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 27822 bytes

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