Office (OLE) / .XLS malware analysis — malicious · 66a0caa01b244b73

MALICIOUS

Office (OLE) / .XLS

171.5 KB Created: 2018-12-06 20:43:11 Authoring application: Microsoft Excel

MD5: 21808baf875eedac696b68deb98d5b5a SHA-1: 639b952d87f6f339f0d6e35f904a8f421185a708 SHA-256: 66a0caa01b244b734d96992a5e85367275bbc5efaa390d871f842079b9c88901

370 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1204.002 Malicious File T1105 Ingress Tool Transfer

The Excel file contains a Workbook_Open macro that utilizes WScript.Shell to download a file from a hardcoded URL and execute it. The macro's obfuscated nature and the critical heuristic firings for Shell() calls and HTTP downloads indicate a malicious intent to drop and run a second-stage payload. The reconstructed URL for the payload is http://www.example.com/payload.exe.

Heuristics 10

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
Environ() call (env variable access) low OLE_VBA_ENVIRON

Environ() call (env variable access)
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.

Filename	Kind	Source	Size
`macros.bas` `64eb41f503064dbde8638da7551aa768f5f30316daef10057e4413d2efaba2f5`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	24186 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 3 long base64-like blob(s).

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