Office (OLE) / .XLS malware analysis — malicious · 6fc9877b40e3210f

MALICIOUS

Office (OLE) / .XLS

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

MD5: df4727d4e4a09093db57e2d6bc5985cd SHA-1: 21caf4eeefb81acc8c55f6ada01116cdbd5200ea SHA-256: 6fc9877b40e3210f9b941f3e2fce3a6384b113b189171cdf8416fe8ea188b719

390 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer T1059 Command and Scripting Interpreter

This Excel file contains a Workbook_Open VBA macro designed to execute arbitrary code. The macro utilizes CreateObject and Shell() calls, and critically, it downloads a file from a remote source using HTTP and saves it to disk, indicating it acts as a downloader for a second-stage payload. The presence of obfuscated code and the specific ClamAV detection signature 'Xls.Malware.Valyria-10032137-0' further support its malicious nature.

Heuristics 10

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
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
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` `c24262a7af85127ff642e568955c0294dcb6759e891954632f8eaa3c35bed234`	vba-macro	oletools.olevba.extract_macros (decoded VBA source)	18293 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 66 long base64-like blob(s).

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