Malicious RTF — malware analysis report

Static analysis result for SHA-256 a3c5880da2fdc1e7…

MALICIOUS

RTF

584.5 KB First seen: 2020-02-04
MD5: 8b140506ec06ac39293346fe55fe9151 SHA-1: 4cb7f1b6b1aee0398a9fe7d6fa0ddfe21571655e SHA-256: a3c5880da2fdc1e7c07bead5af0a5dda6acb0893b39615b512feb82ddfc24d91
184 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple OLE objects and triggers CVE-2017-8570, indicating it's designed to exploit a vulnerability for client execution. The heuristic firings suggest the embedded OLE object data is used to drop a script, likely JavaScript, which is then executed. The specific artifact objdata_01_off0000021e.bin is flagged as suspicious and high-entropy, further supporting the payload delivery.

Heuristics 7

  • 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.
  • 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 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://ocsp.usertrust.com0 In RTF body
    • https://secure.comodo.net/CPS0FIn RTF body
    • http://ocsp.comodoca.com0In RTF body
    • http://www.usertrust.com1In RTF body
    • http://crl.usertrust.com/AddTrustExternalCARoot.crl05In RTF body
    • http://crl.comodoca.com/COMODOSHA256CodeSigningCA.crl0wIn RTF body
    • http://crt.comodoca.com/COMODOSHA256CodeSigningCA.crt0$In RTF body
    • http://crl.usertrust.com/UTN-USERFirst-Object.crl05In RTF body
    • https://www.chiark.greenend.org.uk/~sgtatham/putty/0In 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 273176 bytes
SHA-256: 7b4bded151e6d5b4a4b423182b178fd4900b2d1f55f71a306254e793d656a679
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.92, consistent with packed or encrypted content.
objdata_02_off0008f3df.bin rtf-objdata-decoded RTF \objdata at offset 0x8F3DF 1123 bytes
SHA-256: 263c6a332f8bed14e4d9417cab11f921ef8d301d5b5d655b5a43179ea58c7434
objdata_03_off0008fcde.bin rtf-objdata-decoded RTF \objdata at offset 0x8FCDE 636 bytes
SHA-256: beeb549ebc57e264e8e77fa6b4cfd820bf95bef53865f2e41c70d776aef38923
objdata_04_off0009020e.bin rtf-objdata-decoded RTF \objdata at offset 0x9020E 404 bytes
SHA-256: 392cac683130eb6402c5b549f0e7d1653f531eebb9a09e8b26c73d30cf6c8b98
objdata_05_off00090572.bin rtf-objdata-decoded RTF \objdata at offset 0x90572 937 bytes
SHA-256: e21955e19ee5e9c33caa29d20574aba20d6cc02b855734ac20377ad351eddf3c
objdata_06_off00090d42.bin rtf-objdata-decoded RTF \objdata at offset 0x90D42 2633 bytes
SHA-256: ce081fd28fe7177ff803b92dfff0940839fdacbc316318ce15cbf8889540f4f0

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