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

Static analysis result for SHA-256 41d540dd6adb38df…

MALICIOUS

Office (OLE) / .XLS

301.5 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel
MD5: ad5f2d52fb224d294248f804440efbbf SHA-1: 6e1924c83d6b6520671e5fd9db9a16563da8b823 SHA-256: 41d540dd6adb38df69361d35ad49b7db8799120603d1f91fe13301047aa020ba
348 Risk Score

Malware Insights

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

The sample is a malicious Excel file containing VBA macros. The Workbook_Open event triggers a Shell() call, which is used to download and execute a second-stage payload. The script attempts to construct a URL from concatenated strings, which resolves to 'AppData\dklopjbgnkhoygoh0wkihkyghyggh{etgiwclw{tehgwtewt0npd/hojmsvi.tk/xxx00;tquui'. This indicates a downloader or droppper functionality.

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
7d8307fd327f8cf5cabbe54ccd9598fc6f9c6de7031ff2e7b70f2b40535da79c
vba-macro oletools.olevba.extract_macros (decoded VBA source) 42861 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 shell/COM execution token(s). Carved artifact contains 11 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.