Malicious RTF — malware analysis report

Static analysis result for SHA-256 e2281b917f571839…

MALICIOUS

RTF

461.0 KB First seen: 2021-06-13
MD5: 43bae9ef4a6c9e2160d27b9cf547145d SHA-1: 8fc1a394fc47d7dbd29faa5db01051d63f1a5df7 SHA-256: e2281b917f57183928939b8d37242a3135b563e4ac9c850c2fc9abfda6535035
280 Risk Score

Malware Insights

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

The RTF file contains multiple OLE objects, including composite monikers, and triggers ".objupdate" which are indicative of exploitation attempts. Specifically, the CVE-2017-8570 heuristic indicates the file is designed to drop and execute a script. The embedded artifact objdata_01_off0000735b.bin is flagged as a suspicious extracted artifact containing shellcode command strings.

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.
  • 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.
  • 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
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000bac.bin rtf-objdata-decoded RTF \objdata at offset 0xBAC 121698 bytes
SHA-256: e25b5ccc44076d5e8bca6f35aaed473f76a43d5a65abfb20f467f606bcb00ae8
objdata_01_off0000735b.bin rtf-objdata-decoded RTF \objdata at offset 0x735B 121671 bytes
SHA-256: 01fb29d609239399210d07d5e382479cfb08b2e0c4ff2c998047e400d8ebf7a6
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off00045090.bin rtf-objdata-decoded RTF \objdata at offset 0x45090 2632 bytes
SHA-256: 32e8e449cdc043249ce37c79c9eaf2af80a02cb8175718a8a0ce726d961b7d16
objdata_03_off00046633.bin rtf-objdata-decoded RTF \objdata at offset 0x46633 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7