Malicious RTF — malware analysis report

Static analysis result for SHA-256 247d0161e9f7b192…

MALICIOUS

RTF

141.5 KB First seen: 2019-04-17
MD5: 5e17217d73a61016d5ccef3c746bba1c SHA-1: 1b0a64a578e306b2e6c2c22719aade630ea6dae6 SHA-256: 247d0161e9f7b192b54306889626c3723911587bbca38d9021f638d888a761f5
220 Risk Score

Malware Insights

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

The RTF file contains multiple OLE objects and ".objupdate" directives, indicating it is designed to exploit vulnerabilities. Specifically, the "CVE_2017_8570" heuristic firing confirms the use of a Composite Moniker to drop an SCT script, which is a known technique for executing arbitrary code. The embedded OLE object data, particularly at offset 0xB5D2, is the likely source of this exploit.

Heuristics 6

  • 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.
  • \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 5 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000025.bin rtf-objdata-decoded RTF \objdata at offset 0x25 55571 bytes
SHA-256: ebe28b4b2340161b1c816accd310a12637894f210892fef55ea11d1e50735f4f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.99, consistent with packed or encrypted content.
objdata_01_off00020a57.bin rtf-objdata-decoded RTF \objdata at offset 0x20A57 1056 bytes
SHA-256: 38e0a590df7eaa9868af736886281809be3c0fe6a6a6ea4e0327baa813cb5642
objdata_02_off000212cd.bin rtf-objdata-decoded RTF \objdata at offset 0x212CD 429 bytes
SHA-256: c861ab3ab7d28ef7b028a69afbbfc89c1f5c98f0be9f15b26f0565b7d5605703
objdata_03_off0002165b.bin rtf-objdata-decoded RTF \objdata at offset 0x2165B 1351 bytes
SHA-256: fbfe6031f946bf25c25f9783662a0516de4f34007dcfe7ff53f2b540dbc1df3f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cscript //nologo %vbs%
objdata_04_off00022150.bin rtf-objdata-decoded RTF \objdata at offset 0x22150 2633 bytes
SHA-256: 798252dd8256ec7c0f3355fdbdacc1463a701b0cfdd8d20a5bf75796675244ff