Malicious RTF — malware analysis report

Static analysis result for SHA-256 6262bcfae7b85c6a…

MALICIOUS

RTF

1.04 MB First seen: 2020-05-25
MD5: fdd2d4cb27f4542ac7467c432d46b9ae SHA-1: 6798ffbb650b453c091bb787075eb2a1bfd99c26 SHA-256: 6262bcfae7b85c6ad43b2d8cec89f6b9a5b09c2e903c9316f33a7e6a5cdadb0f
380 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple OLE objects, with specific heuristics indicating the use of Composite Moniker and objupdate to force OLE activation, consistent with CVE-2017-8570. This vulnerability is known to drop and execute SCT scripts. The presence of large amounts of hex-encoded data within the OLE objects suggests a hidden payload. ClamAV detections further confirm the malicious nature of the file and its extracted artifacts.

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.
  • ClamAV: Win.Trojan.VBGeneric-6812985-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Trojan.VBGeneric-6812985-0
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1056KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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 5 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000025.bin rtf-objdata-decoded RTF \objdata at offset 0x25 528157 bytes
SHA-256: 6ece2c34d429e689c1ea93939972ea0f840a41a8cb89509df1687681a55ce293
Detection
ClamAV: Win.Trojan.VBGeneric-6812985-0
Obfuscation or payload: likely
Carved artifact entropy is 8.00, consistent with packed or encrypted content.
objdata_01_off0010766b.bin rtf-objdata-decoded RTF \objdata at offset 0x10766B 1056 bytes
SHA-256: 38e0a590df7eaa9868af736886281809be3c0fe6a6a6ea4e0327baa813cb5642
objdata_02_off00107ee1.bin rtf-objdata-decoded RTF \objdata at offset 0x107EE1 429 bytes
SHA-256: c861ab3ab7d28ef7b028a69afbbfc89c1f5c98f0be9f15b26f0565b7d5605703
objdata_03_off0010826f.bin rtf-objdata-decoded RTF \objdata at offset 0x10826F 1351 bytes
SHA-256: fbfe6031f946bf25c25f9783662a0516de4f34007dcfe7ff53f2b540dbc1df3f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cscript //nologo %vbs%
objdata_04_off00108d64.bin rtf-objdata-decoded RTF \objdata at offset 0x108D64 2633 bytes
SHA-256: 8b52b981393201c0306debe097c2c356eb54ab68ce0bdbf8cf42fe0426e2aa24