Malicious RTF — malware analysis report

Static analysis result for SHA-256 2f381103ce19a55e…

MALICIOUS

RTF

334.3 KB First seen: 2021-07-07
MD5: dc7869d002be9020cb66e8ab39ff7968 SHA-1: d79183bfba505d99029dc363ab5830bf2878857a SHA-256: 2f381103ce19a55e47f96c8008cb09fee5d678ca9ffb25e7d6e5345126449ff3
280 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of malicious OLE object embedding and automatic linking, specifically related to CVE-2017-8570. The document body explicitly instructs the user to 'download the document and click Enable Editing', which is a common lure to bypass security measures. The presence of shellcode command strings and extracted artifacts like 'objdata_01_off00007114.bin' suggests that the file is designed to execute a secondary payload.

Heuristics 8

  • Composite Moniker — CVE-2017-8570 (drops SCT script) critical CVE related CVE_2017_8570
    RTF \objdata decodes to OLE data containing the Composite Moniker — CVE-2017-8570 (drops SCT script) CLSID — the vulnerable control/moniker is embedded directly in the document's object stream, the delivery shape of this exploit. RTF objects auto-render when Word opens the file.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \objupdate forces OLE activation high RTF_OBJUPDATE
    RTF contains \objupdate — forces automatic OLE object instantiation when the document is opened, bypassing user interaction. Almost exclusively seen in Equation Editor exploit documents.
  • 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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000965.bin rtf-objdata-decoded RTF \objdata at offset 0x965 59595 bytes
SHA-256: 5797c327f493a89a4bd05debdcb9688fde5181d5f8e0766791b8a83b1fc1fdf2
objdata_01_off00007114.bin rtf-objdata-decoded RTF \objdata at offset 0x7114 59568 bytes
SHA-256: 4fa3aa3d3fc378f12c8618cbc5f01923054f9e93c9d282e88c35ab4acc504f93
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off000255b3.bin rtf-objdata-decoded RTF \objdata at offset 0x255B3 2632 bytes
SHA-256: a8e170497da15decc11753d202c99c86f7a7ffd2d52481e6b9c79a5403675379
objdata_03_off00026b56.bin rtf-objdata-decoded RTF \objdata at offset 0x26B56 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7