Office (OOXML) malware analysis — malicious · 1307cf49b154993b

MALICIOUS

Office (OOXML)

26.4 KB Created: 2021-08-18 02:04:39 UTC Authoring application: Microsoft Excel 16.0300

MD5: 8dee480570222cb78ee227fef2711d40 SHA-1: 7e2217ba1d5f43af11d49aed81b03340969f290f SHA-256: 1307cf49b154993bb0857e0defa9dae115b16104b9340bdf2689ef3575072fcd

610 Risk Score

Malware Insights

MITRE ATT&CK

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

The sample contains a VBA macro with an Auto_Open subroutine that executes obfuscated shell commands. This macro utilizes WScript.Shell and CreateObject to download a file from the URL 'http://ec2-18-184-17-12.eu-central-1.compute.amazonaws.com/standardchartered/passleak/180821/' and save it as '%TEMP%\Details.dat'. It also attempts to save the response body to '%TEMP%\LeakDetails.dat' and '%TEMP%\leakdetails.log'. The presence of WMI Win32_Process creation further indicates an intent to execute arbitrary code.

Heuristics 14

Shell() call in VBA critical OLE_VBA_SHELL

Shell() call in VBA
WScript.Shell usage critical OLE_VBA_WSCRIPT

WScript.Shell usage
Obfuscated VBA Shell command with URL critical OLE_VBA_OBFUSCATED_SHELL_URL

VBA macro invokes Shell with command text assembled through decoder or string-manipulation functions and includes a URL. This is a high-confidence downloader/dropper pattern, stronger than Shell or URL evidence on their own.
VBA WMI Win32_Process launcher critical OLE_VBA_WMI_PROCESS_CREATE

VBA macro builds or references a WMI moniker for Win32_Process and invokes .Create to start a command. This is a high-confidence macro execution chain that often hides the WMI class name through string concatenation or helper functions.
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.
ClamAV: Doc.Downloader.Valyria-10026858-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Downloader.Valyria-10026858-0
ClamAV detection on extracted artifact critical EXTRACTED_FILE_CLAMAV

ClamAV flagged at least one file extracted from inside this sample. Even when the wrapping document carries no AV detection of its own, a hit on the carved artifact is a strong indicator the sample is a delivery vehicle.
Auto_Open macro high OLE_VBA_AUTO

Auto_Open macro
CreateObject call high OLE_VBA_CREATEOBJ

CreateObject call
GetObject call high OLE_VBA_GETOBJ

GetObject 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
Environ() call (env variable access) low OLE_VBA_ENVIRON

Environ() call (env variable access)
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://ec2-18-184-17-12.eu-central-1.compute.amazonaws.com/standardchartered/passleak/180821/

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `ef24cac1b674956f2848eadd15826ca8fb710f33a4d25618b44d79c09298fc14`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	4717 bytes
`vbaProject_00.bin` `05143f0f76c290d9bde392d7c6b65691f220ac5ee51741bc4213389c8191849d`	vba-project	OOXML VBA project: xl/vbaProject.bin	18432 bytes
Detection ClamAV: Doc.Downloader.Valyria-10026858-0 Obfuscation or payload: unlikely

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