Office (OOXML) malware analysis — malicious · 39c370648e62fa53

MALICIOUS

Office (OOXML)

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

MD5: 8bc05c52f6e0b694d08112f23b2ed596 SHA-1: f69dbd82631afeacdf381ec11d9a268acf23f188 SHA-256: 39c370648e62fa53afe2a6ef4392032d71b6f17bd64edfbeb5859235983331dc

610 Risk Score

Malware Insights

MITRE ATT&CK

T1059.005 Visual Basic T1105 Ingress Tool Transfer T1204.002 Malicious File T1071.001 Web Protocols

The sample contains VBA macros with an Auto_Open subroutine that executes a shell command. This script uses WScript.Shell to download a payload from the embedded URL 'http://ec2-18-184-17-12.eu-central-1.compute.amazonaws.com/standardchartered/employees/incident/180821/' and saves it to disk as 'Details.dat' in the temporary directory. The use of WMI to create a process indicates an attempt to execute the downloaded payload.

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/employees/incident/180821/

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`macros.bas` `18f92ec0603e152be1d9ba4ff6c42ce95ef86d2f7c9d72833c54272d1d2df657`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	4726 bytes
`vbaProject_00.bin` `1524a364458287b5e2f74d0c2e7ae63330b7e2a0f622dedea11be54adaf04dd2`	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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