Malicious RTF — malware analysis report

Static analysis result for SHA-256 8ed01613e3f8a9b2…

MALICIOUS

RTF

391.6 KB First seen: 2019-06-27
MD5: 2bf48ff9e270d83626fc6a1f5190b508 SHA-1: 0a67a4868efa2d464240a4569b75aadb257448d7 SHA-256: 8ed01613e3f8a9b20fb664e628843c4f22069825018ad5195fcdb41b135efad6
344 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of malicious activity, including OLE object data, a composite moniker, and a PE header within hex data. Crucially, it exploits CVE-2017-8570, which is known to drop a script file. An extracted artifact, objdata_05_off00006688.bin, is also flagged as suspicious and likely contains the second-stage 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.
  • 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.
  • OLE object data medium RTF_OBJDATA
    RTF contains 6 \objdata section(s) — embedded OLE objects
  • Suspicious extracted artifact info 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.
  • 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://nsis.sf.net/NSIS_Error In RTF body

Extracted artifacts 6

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003af4.bin rtf-objdata-decoded RTF \objdata at offset 0x3AF4 885 bytes
SHA-256: 7d5f88680e60b61c3804b4e958745d940ae073cb6f167cc9e0d1a27e8996ab45
objdata_01_off00004211.bin rtf-objdata-decoded RTF \objdata at offset 0x4211 612 bytes
SHA-256: c62851521e10316dfd43f2b6ee67cc27e2a24456bb346c8fa9dc4a6d6e21d526
objdata_02_off0000470b.bin rtf-objdata-decoded RTF \objdata at offset 0x470B 464 bytes
SHA-256: e703848bebd5a70ed3890f101964afa809d470068426f899f139fe667cfa40f0
objdata_03_off00004adf.bin rtf-objdata-decoded RTF \objdata at offset 0x4ADF 820 bytes
SHA-256: d6e0de80a1802cce16fd208d08beb938c29c6d62984b89d9b3f972281ec4f244
objdata_04_off000051ae.bin rtf-objdata-decoded RTF \objdata at offset 0x51AE 2633 bytes
SHA-256: fe11c27d916ab897eb94064e9631d8a29c847a6db39259bef31578da8d19fdf5
objdata_05_off00006688.bin rtf-objdata-decoded RTF \objdata at offset 0x6688 187343 bytes
SHA-256: 53a0bcf85df398cd40235b5339899be484fcfeb3b08aa7537680e108f19b8f86
Detection
ClamAV: Win.Packer.MalwareCrypter-6642003-1
Obfuscation or payload: likely
Carved artifact entropy is 7.87, consistent with packed or encrypted content.