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

Static analysis result for SHA-256 5a025699bc510a4a…

MALICIOUS

Office (OLE) / .XLS

1.61 MB Created: 2016-04-08 13:33:00 Authoring application: Microsoft Excel First seen: 2023-10-18
MD5: 858bdd40febca7841f7da620ead3f4f1 SHA-1: b4a6b76efe58447117e026293797a77ea2a335c3 SHA-256: 5a025699bc510a4ad9c23718e7ad845899c17dc4a061569941b8e36a61791196
482 Risk Score

Malware Insights

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

The sample is a macro-enabled Excel spreadsheet containing an obfuscated auto-exec loader within its VBA macros. The Workbook_Open event is triggered upon opening, which then uses WScript.Shell and CreateObject to execute a payload. This payload is likely designed to download and run a second-stage malicious file from the embedded URL http://www.frez.co.uk.

Heuristics 12

  • Shell() call in VBA critical OLE_VBA_SHELL
    Shell() call in VBA
  • WScript.Shell usage critical OLE_VBA_WSCRIPT
    WScript.Shell usage
  • 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.
  • 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
  • GetObject call high OLE_VBA_GETOBJ
    GetObject 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.
  • Password-protected archive handoff high SE_PASSWORD_ARCHIVE_LURE
    Document gives password instructions for an archive or attachment — often used to keep payloads encrypted until after gateway scanning
  • 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
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://www.frez.co.uk

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
macros.bas
efc3b15eb92c34b9f51b069d1f11ab252df4d9a9f3a78f0bec4de93e50d2ad22		 vba-macro oletools.olevba.extract_macros (decoded VBA source) 1444515 bytes
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 2 eval/decoder/string-building token(s).

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