Office (OOXML) malware analysis — malicious · cdc14557fde2f7b6

MALICIOUS

Office (OOXML)

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

MD5: 9dbbe2919b92707e0eff610910e3be01 SHA-1: 5ca7aaa99c49333711e1a7daf14d7dea1864998e SHA-256: cdc14557fde2f7b61572287e2ddc09747e8b74f43c9be4097fc8e94c8fe9c1c1

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 a shell command. This command is obfuscated and contains a URL, indicating it's designed to download and execute a second-stage payload. The macro uses WScript.Shell and WMI to create a process, and it attempts to download content from the specified URL to temporary files named 'Details.dat', 'TEDetails.dat', and 'IncDetails.log'. The ClamAV detection 'Doc.Downloader.Valyria-10026858-0' further supports its malicious nature as a downloader.

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` `8c676eb052baeb704439ffc7d6e202d923eb7f60c16247b74732c2f80de6bc53`	vba-macro	oletools.olevba.extract_macros (decoded VBA source from OOXML)	4726 bytes
`vbaProject_00.bin` `0194ee76d5163a71794290cba98e7260e8535a115a8d47b8068b8300b7b26854`	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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