Office (OLE) / .XLS malware analysis — malicious · 6cec9b24677f0912

MALICIOUS

Office (OLE) / .XLS

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

MD5: 9d7381c08b29bfa3c3e53f2780bd16a5 SHA-1: c9c161ab7219bf81cbff75593dcce091bb4562b4 SHA-256: 6cec9b24677f0912fe91b0b40836752be09888e6c2b1783f51c9a7aa6827b864

490 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer

The critical OLE_VBA_OBFUSCATED_AUTOEXEC_LOADER and OLE_VBA_HTTP_DROP_EXEC heuristics indicate that the VBA macros are designed to download and execute a second-stage payload. The Workbook_Open macro is used as an auto-execution trigger, and the script attempts to download content from a URL and save it as 'macros.bas' in the user's profile directory. The use of Shell() and WScript.Shell confirms execution capabilities.

Heuristics 12

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.Malware.Valyria-10032137-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Malware.Valyria-10032137-0
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
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` `018842088b27cb3c0aad7f6a54c8a14b44ff93831b738c0d9af9408a26168cf5`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	61976 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 141 long base64-like blob(s).

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