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

Static analysis result for SHA-256 9be1c85ab9429ebd…

MALICIOUS

Office (OLE) / .XLS

560.0 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel
MD5: b6fa8adcc5171921b8d4d08f49f47dac SHA-1: 0ffb2457ab42e2dd949b99ea680b80436ad9853c SHA-256: 9be1c85ab9429ebd87ab37ceb24e2b7700266cf911a62c9f1597454ce234f912
348 Risk Score

Malware Insights

MITRE ATT&CK
T1059.005 Visual Basic T1059.001 PowerShell T1059.003 Windows Command Shell T1204.002 Malicious File T1105 Ingress Tool Transfer

The sample is a malicious Excel file containing VBA macros. The Workbook_Open macro is triggered upon opening, which uses WScript.Shell to create a file named 'macros.bas' in the AppData directory. It then attempts to download and execute a payload from the reconstructed URL 'http://fyf.dklopjbgnkhoygoh0wkihkyghyggh{etgiwclw{tehgwtewt0npd/hojmsvi.tk/xxx00;tquui'. The use of Shell() and WScript.Shell, along with the auto-execution of the macro, indicates a downloader pattern.

Heuristics 9

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • 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.
  • 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 macros detected medium OLE_VBA_MACROS
    Document contains VBA macro code
  • Environ() call (env variable access) low OLE_VBA_ENVIRON
    Environ() call (env variable access)

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
a5aafba106479c65918ec62ec50f8a1537e248c200b4f37e141824d3e3a54f2f		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 42660 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s). Carved artifact contains 14 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.

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