Office (OOXML) / .XLSX malware analysis — malicious · 95fae63a81594640

MALICIOUS

Office (OOXML) / .XLSX

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

MD5: cd4d86e864d97f3cc7afe3049cd419c2 SHA-1: 4d25487086ec36eb8f057db19cffdf3e021cd210 SHA-256: 95fae63a815946403be29f5136054d5529fc346f55648a3532e2fb9d54f6caec

380 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1059.003 Windows Command Shell T1204.002 Malicious File T1105 Ingress Tool Transfer

The OOXML file contains a VBA macro with an Auto_Open function that utilizes WScript.Shell to execute a command. This command is Base64-decoded and reveals a URL from which a second-stage executable is downloaded and run. The presence of an 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/EmrzVnkezMkCRUQ.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` `57a7b6e89bdee7372210981aff02dc77216f1856d5d8cefef51cf8e6d41c1500`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	20730 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` `2a73e54c7a7ead84b069aa356a0e9c5fed4feeda1624dad64979f9903f0f8e7b`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject2.bin	10240 bytes
`ooxml_oleobject_01_ole10native_00.bin` `667c629637522910608559edc40330e932ffb5bbd5144d663102213eeddf5b96`	ole-package	OOXML xl/embeddings/oleObject2.bin Ole10Native stream: Ole10Native	7496 bytes
`ooxml_oleobject_02.bin` `5659a03f1cd8950011a50e6abc4537b232b4acd8bc0ad594057c461932a332d6`	ooxml-ole-object	OOXML embedded OLE part: xl/embeddings/oleObject1.bin	3584 bytes
`ooxml_oleobject_02_ole10native_00.bin` `a7a2532e9f14ce4ccfe4fd599ea3df33baef2d648293e5d417ca3c826ac55248`	ole-package	OOXML xl/embeddings/oleObject1.bin Ole10Native stream: Ole10Native	961 bytes
`ooxml_oleobject_03.bin` `837a1b60858763f6434905de9eeceb131f1fab0a9197b6353d5438dd6973ca96`	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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