Malicious RTF — malware analysis report

Static analysis result for SHA-256 e8688df0ee4b4ef4…

MALICIOUS

RTF

2.48 MB Authoring application: Riched20 6.3.9600 First seen: 2018-06-25
MD5: 918ed3e52f7bbfc292b6f8e30cc34121 SHA-1: 6dc187cfb4112b3b73a79c89822282b2d0c020bf SHA-256: e8688df0ee4b4ef4c329752741643799693312e840128e36e6e411c55586e4b7
500 Risk Score

Malware Insights

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

The RTF file contains embedded OLE objects, specifically exploiting the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution when the embedded object is activated. The presence of PE headers within the hex-encoded data further suggests a malicious payload is hidden within the object. The file is classified as malicious due to this exploit.

Heuristics 12

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • 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: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • \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.
  • Package object class high RTF_OBJCLASS_PACKAGE
    OLE Package object — can wrap arbitrary files
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2587KB 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 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000ef.bin rtf-objdata-decoded RTF \objdata at offset 0xEF 1293606 bytes
SHA-256: 028a3c01211c47e3cea2e4c9047cee6bdf32fa741732ca17b0a467ea308c634d
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.77, consistent with packed or encrypted content.
objdata_01_off00277b8a.bin rtf-objdata-decoded RTF \objdata at offset 0x277B8A 3980 bytes
SHA-256: cd8b2e5d5b7833d0f836687ed7bcf15f353901d010456396c255f85c393d10ed
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\administrator.exe &��D$,f-Q���%
objdata_02_off00279dd0.bin rtf-objdata-decoded RTF \objdata at offset 0x279DD0 3546 bytes
SHA-256: 4ba2fa372612e642152c80a0a416f7b327d464b9a4bd9c72cf0e8b66aa5ddb64
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\administrator.exe A C