Office (OOXML) / .XLSX malware analysis — malicious · 8e9ce26efc6bfe9f

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: 4b66f99a113858da9f12c9b80a5163f8 SHA-1: 8ae81be3377e7a1d145433feb52472cf78158c4f SHA-256: 8e9ce26efc6bfe9f15da163f7fe507eb4372589abd6ffec9489c712c6887f976

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 subroutine. This macro utilizes WScript.Shell and CreateObject to execute a Base64-decoded command that downloads a second-stage executable from the URL http://88.218.16.38/PcKZudZGCtvEohA.exe. The presence of the Equation Editor OLE object is also noted, which can sometimes be used for exploit delivery.

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://88.218.16.38/PcKZudZGCtvEohA.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` `9b64db794843aae3a7635c708f2a58cbf071abf9c7c2597c38f8ef6f039d13f2`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	20726 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` `e585e3c36f79632c5608f8dd1b80eb2c61db702a8e878bd8bb7c28bd75d25810`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	10240 bytes
`ooxml_oleobject_01_ole10native_00.bin` `004c2dbec1f6d9494b99d30673a78cf026a292650fb02c91c502ee8b664151f4`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	7498 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` `7d836a61784fbec5874a30e9fe082aaa11fbbbc274b3892d180cf483f04e6555`	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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