Malicious RTF — malware analysis report

Static analysis result for SHA-256 d1ace0dfb9f9c718…

MALICIOUS

RTF

659.6 KB First seen: 2019-01-12
MD5: b2911d71184a6ea01246f37add48317c SHA-1: 04b21172abd478b9df9d7b3efe329fe4d65a3317 SHA-256: d1ace0dfb9f9c7189ddceba5ac592f39fc044254e469ce73dfe2a6709bcdd167
462 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of exploitation, including OLE object data, an Equation Editor CLSID, and a PE header in hex data. The embedded URL suggests a download or redirection to a malicious payload. The presence of extracted artifacts with high-entropy and shellcode command strings further supports the malicious nature of the file, likely leading to the execution of a second-stage malware.

Heuristics 11

  • 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
  • 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.Packer.MalwareCrypter-6642003-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Packer.MalwareCrypter-6642003-1
  • 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.
  • INCLUDETEXT/INCLUDEPICTURE remote URL high RTF_INCLUDE_REMOTE
    RTF document uses INCLUDETEXT or INCLUDEPICTURE with an http:// URL — Word can fetch the remote content on open depending on Office version and external-content settings, enabling remote template injection, NTLM capture via redirects, or payload delivery
  • 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 7 \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.
  • 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://test1x.ru/newdfbuildsd/t.php?thread=0&stats=send In RTF body

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00008676.bin rtf-objdata-decoded RTF \objdata at offset 0x8676 400 bytes
SHA-256: fa79b00817f7495218632b8aca05100fc72b724a674512e970aa8642ceaa44bc
objdata_01_off000089c9.bin rtf-objdata-decoded RTF \objdata at offset 0x89C9 308475 bytes
SHA-256: d8c5b3a06b9c66ee8a9263a0d2805a784c1e77ba929b5ffa4544bee3d91a70d2
Detection
ClamAV: Win.Packer.MalwareCrypter-6642003-1
Obfuscation or payload: likely
Carved artifact entropy is 7.79, consistent with packed or encrypted content.
objdata_02_off0009f3fd.bin rtf-objdata-decoded RTF \objdata at offset 0x9F3FD 372 bytes
SHA-256: 8116eaa3fd7cd40a329a7e50e7c833dc7de210bca9373e00f1712abafe7b5329
objdata_03_off0009f719.bin rtf-objdata-decoded RTF \objdata at offset 0x9F719 2590 bytes
SHA-256: 11c301240587dc283099341a91764bda06d326ba14f1861f8caf4f2b1c4284b4
objdata_04_off000a0b8b.bin rtf-objdata-decoded RTF \objdata at offset 0xA0B8B 722 bytes
SHA-256: 53e3b7e9f6d57fce9016b943fe179da1ad444f8850532a507b0937972911db85
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell")
objdata_05_off000a11b9.bin rtf-objdata-decoded RTF \objdata at offset 0xA11B9 2620 bytes
SHA-256: 364acb5a22b102e1bc3d515236e29b7edf1f103d59dc337dc55dd5487bec6a90
objdata_06_off000a27b5.bin rtf-objdata-decoded RTF \objdata at offset 0xA27B5 4681 bytes
SHA-256: 61be60fbb4c26d07954969e353d178f3a4e0982dff3e806ec67d1c5750529f24

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