Office (OOXML) / .XLSM malware analysis — malicious · 6cf72c0503a733c2

MALICIOUS

Office (OOXML) / .XLSM

412.5 KB Created: 2020-05-29 08:47:30 UTC Authoring application: Microsoft Excel 16.0300

MD5: 2e020fd3d772f59d8b84d7c3d143b615 SHA-1: 2283ee78f44b38b0ef2453255fe61393982fa874 SHA-256: 6cf72c0503a733c2b799ff4d377dbcd1b992a49c69c833dc1cd4ffa7de35a487

384 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.001 PowerShell T1105 Ingress Tool Transfer T1204.002 Malicious File

The VBA macro contains a Workbook_Open subroutine that decodes and executes a PowerShell command. This command downloads a second-stage executable named 'siihost.exe' from 'http://111.90.149.244/siihost.exe' into the temporary directory and then executes it. The use of WScript.Shell and CreateObject, along with the Base64-decoded command, strongly indicates a downloader functionality.

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 Base64-decoded Shell command stager critical OLE_VBA_BASE64_SHELL_COMMAND_STAGER

VBA auto-exec macro decodes Base64 string literals into command or script-launch text and executes the result with Shell. This catches cmd/cscript/PowerShell/VBS launchers hidden from plain keyword matching.
ClamAV: Xls.Downloader.DridexGreen09213-9890103-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Xls.Downloader.DridexGreen09213-9890103-0
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 project inside OOXML medium OOXML_VBA

Document contains a VBA project — VBA macros present
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.
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://111.90.149.244/siihost.exe

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `81c4693c8e76a3d3e4d541f73a4d13d4fe0ee400e2f344b404494326583fdcfb`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	2958 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).
`vbaProject_00.bin` `5456ac14777daeecf6d548c39ef26853bbefcef89e7ea898882d86811e0d00d2`	vba-project	OOXML VBA project: xl/vbaProject.bin	19456 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 long base64-like blob(s).

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