Office (OOXML) / .XLSX malware analysis — malicious · a9bc2d1626eb464a

MALICIOUS

Office (OOXML) / .XLSX

45.8 KB Created: 2020-02-01 18:28:07 UTC Authoring application: Microsoft Excel 12.0000

MD5: a04f90ed1721dc3f670d5095751261bf SHA-1: 1b5fe3aaf7621e73373245a3c03910e931b1fc23 SHA-256: a9bc2d1626eb464a4433b12fe4d01c1acc1721156e162a598e65e669d1d69f51

380 Risk Score

Malware Insights

MITRE ATT&CK

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

The OOXML file contains a VBA macro with an Auto_Open function that utilizes WScript.Shell and CreateObject to execute a Base64-decoded command. This command downloads and executes a PE file from the URL http://88.218.16.37/Srr45MA8prCJUWh.exe, indicating a downloader or droppper functionality.

Heuristics 9

Equation Editor OLE object high CVE related OLE_EQUATION_EDITOR

Embedded OLE object xl/embeddings/oleObject3.bin contains the Equation Editor CLSID, the legacy component exploited by CVE-2017-11882, CVE-2018-0802, and CVE-2018-0798.
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.

URL http://88.218.16.37/Srr45MA8prCJUWh.exe
Auto_Open macro high OLE_VBA_AUTO

Auto_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
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 project inside OOXML medium OOXML_VBA

Document contains vbaProject.bin — VBA macros present
Embedded OLE object medium OOXML_OLE_OBJECT

Document contains an embedded OLE object

Extracted artifacts 9

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `a990df86de33ba6ef1f44c9e48f09db383b27824efc4845598871f3ff09fc6c8`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	20738 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact contains 1 shell/COM execution token(s). Carved artifact contains 1 long base64-like blob(s). Carved macro source contains an auto-exec entry point and execution/download terms.
`ooxml_oleobject_00.bin` `090883485a1c24e2872682318c19530f280710960782d479ef195bf08d2617e8`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject3.bin	5936 bytes
`ooxml_oleobject_01.bin` `31a39659b0abfc1b268bdddcdd38704e8abdd01834500b3a09139585e48b2e40`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	10240 bytes
`ooxml_oleobject_01_ole10native_00.bin` `e67c70bd73a3c344062d02b3defe50341ac034c0f7161bf87e790b2fca78e12a`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	7510 bytes
`ooxml_oleobject_02.bin` `7975e129018037a51fdd6c36eaa7423c865bdb477145e3ba36daec873ed8d49f`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	3584 bytes
`ooxml_oleobject_02_ole10native_00.bin` `d9384e3319b5058b992d4934e73df8752f6e2cb31daae3a7a8eb4eae2ad11d13`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native	967 bytes
`ooxml_oleobject_03.bin` `b714580098e954779560544cb4bffb8bb725110651309c95fe015e744b1a27a7`	ooxml-ole-object	OOXML embedded OLE part: xl/vbaProject.bin	43008 bytes
Detection ClamAV: No threats found Obfuscation or payload: likely Carved macro source contains an auto-exec entry point and execution/download terms.
`emf_00.emf` `979dde2aed02f077c16ae53546c6df9eed40e8386d6db6fc36aee9f966d2cb82`	ooxml-emf	OOXML EMF part: xl/media/image1.emf	4968 bytes
`emf_01.emf` `4d4d1e7b04c99dcb8e885915068ad6f74cc2333e91580cdae5ccaa00c427247f`	ooxml-emf	OOXML EMF part: xl/media/image2.emf	1536 bytes

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