Malicious RTF — malware analysis report

Static analysis result for SHA-256 b9f6880bdb535c20…

MALICIOUS

RTF

1.86 MB Authoring application: Riched20 6.3.9600 First seen: 2026-05-24
MD5: 4f20f9c7128d525d2a31c9e17e652954 SHA-1: aa15b5b441ff94d8003d75bb75baf7ebce0dcd94 SHA-256: b9f6880bdb535c20df048bacaaf7587f48f0bd8e98cefb258ef8915836126fd7
360 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF document contains multiple indicators of exploitation for CVE-2017-8570 and CVE-2017-0199, leveraging OLE objects and composite monikers. These vulnerabilities are known to facilitate the automatic download and execution of arbitrary code, likely a second-stage payload. The presence of embedded OLE objects and excessive hex data further supports this attack pattern.

Heuristics 9

  • 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.
  • CVE-2017-0199 / CVE-2017-8759 (OLE2Link auto-activated remote loader) critical CVE related RTF_OLE2LINK_REMOTE_MONIKER_LOADER
    RTF embeds an OLE2Link object that is force-activated with \objupdate (no user interaction on open) and fetches a remote second stage — through an INCLUDETEXT/INCLUDEPICTURE field or the OLE object's own moniker. This is the OLE2Link auto-update attack path shared by CVE-2017-0199 (server returns an HTA/scriptlet) and CVE-2017-8759 (server returns a SOAP WSDL the .NET parser compiles). Office processes the fetched response through the same code path; the specific CVE depends on the now-unreachable server content type.
  • 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1727KB 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 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
🗂 Part of campaign: shared payload 51ef705eef 49 samples

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000d70ef.bin rtf-objdata-decoded RTF \objdata at offset 0xD70EF 408264 bytes
SHA-256: 2e17a7d62cc4a73f1a8b38892c7cadeee9942138929866331088543b6817fab5
objdata_01_off000dd89e.bin rtf-objdata-decoded RTF \objdata at offset 0xDD89E 408237 bytes
SHA-256: 04591b21d24e8d0b5242686e1d2cdba47cbc3951371a54619814b7f9fb0c89ea
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off001ace2b.bin rtf-objdata-decoded RTF \objdata at offset 0x1ACE2B 2632 bytes
SHA-256: 51ef705eef602ac6eb91c2063c8f50d4e54b5e051b60429031d41133bc7df645
objdata_03_off001ae3ce.bin rtf-objdata-decoded RTF \objdata at offset 0x1AE3CE 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7