Malicious RTF — malware analysis report

Static analysis result for SHA-256 86d32b98fdb94da5…

MALICIOUS

RTF

334.9 KB First seen: 2021-07-10
MD5: 09c7df0ed8473bbcfdce8f373f529ad2 SHA-1: 5fd33d87895baa8bd10b8091316bda2e479589ff SHA-256: 86d32b98fdb94da5c69ba7d65d2b66f4badda895ad0ac6505aaac27e6c72e73a
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 59599 bytes
SHA-256: 482b69e931d26ac93345230a246e2602cfa17a4afba1d83b6746a5d08a74d312
objdata_01_off0000735b.bin rtf-objdata-decoded RTF \objdata at offset 0x735B 59572 bytes
SHA-256: f22518bfe092ceee7849ff35fb8075aed2b3dc51e91de6fa72d2942b6ff7b1fc
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off00025802.bin rtf-objdata-decoded RTF \objdata at offset 0x25802 2632 bytes
SHA-256: a8e170497da15decc11753d202c99c86f7a7ffd2d52481e6b9c79a5403675379
objdata_03_off00026da5.bin rtf-objdata-decoded RTF \objdata at offset 0x26DA5 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7