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

Static analysis result for SHA-256 1767a9206deb4dbb…

MALICIOUS

Office (OLE) / .XLS

660.0 KB Created: 2020-10-05 09:30:22 Authoring application: Microsoft Excel
MD5: b4630469c1eb7acfd7c9ef041fadcfa0 SHA-1: 4453db6c25f2e4ed9d1fae3549adda8cca6de876 SHA-256: 1767a9206deb4dbba96ab368f45b43e4603af97e631940bbd1947e70b932f0af
482 Risk Score

Malware Insights

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

This XLS file contains obfuscated VBA macros designed to execute automatically upon opening. The Workbook_Open macro utilizes WScript.Shell to download and execute a second-stage payload, as indicated by critical heuristics for shell execution and HTTP download/save functionality. The specific download URL and executed payload are not directly visible due to obfuscation, but the intent is clear.

Heuristics 11

  • 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.
  • Obfuscated auto-exec VBA loader critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER
    Auto-exec VBA reconstructs strings with a heavy custom decoder (numeric char-array, repeated hex-string decode, or junk-token Replace removal) and feeds them to a COM-instantiation or execution sink. This obfuscated-loader shape keeps CreateObject/Shell/URL indicators out of the macro source.
  • ClamAV: Xls.Macro.Obfuscation-9804250-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Xls.Macro.Obfuscation-9804250-0
  • 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
  • Suspicious extracted artifact info 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
e241b4202c113e78669c114847888c8d4d15b84fa6111afe314acce8eb225142
vba-macro oletools.olevba.extract_macros (decoded VBA source) 17259 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 69 long base64-like blob(s).