Malicious RTF — malware analysis report

Static analysis result for SHA-256 f9502497ef9bd3ba…

MALICIOUS

RTF

1.73 MB First seen: 2019-10-01
MD5: cd82fc16c798183e7bc803a42b2271e4 SHA-1: f24d63fa1ee962fb19432f2ca6adde4d75f419d6 SHA-256: f9502497ef9bd3ba6d0004dd51981455ad141ac4b8bf1b7b1d8fc8485c1f2b7a
242 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of malicious activity, including the exploitation of CVE-2017-8570 via composite moniker and embedded OLE objects. The heuristic firings strongly suggest that the file is designed to drop and execute a script, likely a second-stage payload, as indicated by the presence of shellcode API strings in an extracted artifact. The embedded OLE object data, particularly objdata_01_off0000021e.bin, is a primary suspect for containing the malicious script.

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.
  • \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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1641KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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
  • Suspicious extracted artifact medium 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://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 7

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000025.bin rtf-objdata-decoded RTF \objdata at offset 0x25 229 bytes
SHA-256: bdf6de0a64b3411ca5229f989a8704bb9f2ac8eac0d3b0c83ab62136585dd012
objdata_01_off0000021e.bin rtf-objdata-decoded RTF \objdata at offset 0x21E 820963 bytes
SHA-256: 0a00e28e5efbb49d4b57f77c8e576b677ead6da59a3b44f28d448266ada78c28
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_MSF_REVERSE, SC_STR_VIRTUALALLOC, SC_STR_LOADLIBRARY Static shellcode analysis recovered API/import strings: LoadLibraryExA, VirtualAlloc, GetProcAddress, ExitProcess
objdata_02_off001a964b.bin rtf-objdata-decoded RTF \objdata at offset 0x1A964B 1123 bytes
SHA-256: 263c6a332f8bed14e4d9417cab11f921ef8d301d5b5d655b5a43179ea58c7434
objdata_03_off001a9f4a.bin rtf-objdata-decoded RTF \objdata at offset 0x1A9F4A 31700 bytes
SHA-256: d4a1288d7e1e89b8424faf9a360d1200ca1fa2aa5a80b059536b6305279af68e
objdata_04_off001b972a.bin rtf-objdata-decoded RTF \objdata at offset 0x1B972A 404 bytes
SHA-256: 392cac683130eb6402c5b549f0e7d1653f531eebb9a09e8b26c73d30cf6c8b98
objdata_05_off001b9a8e.bin rtf-objdata-decoded RTF \objdata at offset 0x1B9A8E 937 bytes
SHA-256: e21955e19ee5e9c33caa29d20574aba20d6cc02b855734ac20377ad351eddf3c
objdata_06_off001ba25e.bin rtf-objdata-decoded RTF \objdata at offset 0x1BA25E 2633 bytes
SHA-256: ce081fd28fe7177ff803b92dfff0940839fdacbc316318ce15cbf8889540f4f0