Malicious RTF — malware analysis report

Static analysis result for SHA-256 2251bf498a8de1f5…

MALICIOUS

RTF

1.27 MB First seen: 2019-08-04
MD5: 5582f964338816fdc9e6240cf825c9e9 SHA-1: 9bb3a1538623b3c313d0ae0fa32ff70d8e971f4d SHA-256: 2251bf498a8de1f5840a86e2e3fb890cd6bdbfa022605dfc7b884a3a7de075ae
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of malicious activity, including OLE object data, excessive hex data, and a critical firing for CVE-2017-8570. This vulnerability is known to be used for dropping SCT scripts, which are then executed. The presence of a Composite Moniker further supports the exploitation of this vulnerability to achieve arbitrary code execution.

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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1155KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 9 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • 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.digicert.com0O In RTF body
    • http://ocsp.digicert.com0CIn RTF body
    • https://www.digicert.com/CPS0�In RTF body
    • http://crl3.digicert.com/sha2-assured-ts.crl02�0�.�,http://crl4.digicert.com/sha2-assured-ts.crl0��In RTF body
    • http://cacerts.digicert.com/DigiCertSHA2AssuredIDTimestampingCA.crt0In RTF body
    • http://cacerts.digicert.com/DigiCertAssuredIDRootCA.crt0��In RTF body
    • http://crl4.digicert.com/DigiCertAssuredIDRootCA.crl0:�8�6�4http://crl3.digicert.com/DigiCertAssuredIDRootCA.crl0PIn RTF body
    • https://www.digicert.com/CPS0In RTF body
    • http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 8

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000025.bin rtf-objdata-decoded RTF \objdata at offset 0x25 205 bytes
SHA-256: 980870ba17beb12f03c3941a0cfa655d820816cec9104090156a6ea6ece5ce8a
objdata_01_off000001ee.bin rtf-objdata-decoded RTF \objdata at offset 0x1EE 577811 bytes
SHA-256: 74d3ba1c12f088a135e5f5a7376e67232a31fb9f179b05751a6c572633e60387
objdata_02_off00132a7b.bin rtf-objdata-decoded RTF \objdata at offset 0x132A7B 1004 bytes
SHA-256: de57d2083ef5e021ec705be7e3dd4b0e90d1d2f7950e0bc7ffde2709f639f965
objdata_03_off0013328c.bin rtf-objdata-decoded RTF \objdata at offset 0x13328C 31676 bytes
SHA-256: 8e1be3feb782a829ff258a0e054e4c260ab6864e307e975e6874709ef91bf7cf
objdata_04_off00142a3c.bin rtf-objdata-decoded RTF \objdata at offset 0x142A3C 359 bytes
SHA-256: 357be353baa88dc3743707bade3b7e68e8e017f02553817dd77495fda9a64957
objdata_05_off00142d46.bin rtf-objdata-decoded RTF \objdata at offset 0x142D46 866 bytes
SHA-256: 5d0695c0b0c9feed62b1faa3e75242a3007ac483afd76a69c04e9ed6b9541365
objdata_06_off00143488.bin rtf-objdata-decoded RTF \objdata at offset 0x143488 2633 bytes
SHA-256: fe11c27d916ab897eb94064e9631d8a29c847a6db39259bef31578da8d19fdf5
objdata_07_off001449a0.bin rtf-objdata-decoded RTF \objdata at offset 0x1449A0 2601 bytes
SHA-256: 67ff079a9b0f053ca2843811d9da7a8fdedc7d9d377ef39d09dde148b9657c7f

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