Malicious RTF — malware analysis report

Static analysis result for SHA-256 86e158bb7bb2b2ff…

MALICIOUS

RTF

391.4 KB First seen: 2019-01-11
MD5: 99e1c71004c539d6a29a945e38771bb9 SHA-1: c7dfab7f7a16d3b243f5b7e7ed9c22c544178744 SHA-256: 86e158bb7bb2b2ff284bb948720cf9672cc05f85ddab05bcb5a41e3eabf802bb
182 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.
  • 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.

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_off0000021a.bin rtf-objdata-decoded RTF \objdata at offset 0x21A 186784 bytes
SHA-256: e8c7bf5e333f15184b8648d6fc5ccc798cc81a5273c7489bc0ed6d0803757db7
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.87, consistent with packed or encrypted content.
objdata_02_off0005f05c.bin rtf-objdata-decoded RTF \objdata at offset 0x5F05C 1092 bytes
SHA-256: d4bc1acb790f4d56cd06070639d405330d630c9694d98fa2b3b82c6bf73da07d
objdata_03_off0005f917.bin rtf-objdata-decoded RTF \objdata at offset 0x5F917 636 bytes
SHA-256: beeb549ebc57e264e8e77fa6b4cfd820bf95bef53865f2e41c70d776aef38923
objdata_04_off0005fe41.bin rtf-objdata-decoded RTF \objdata at offset 0x5FE41 393 bytes
SHA-256: cc434f8b829894f9e2d49a62c39440162c7bcebb137b5685ff63adca2384b98a
objdata_05_off00060187.bin rtf-objdata-decoded RTF \objdata at offset 0x60187 914 bytes
SHA-256: 27bd5b1e1679863c8cd0257c9eb6b6ee3106b285add9281353de171771ae84d6
objdata_06_off00060912.bin rtf-objdata-decoded RTF \objdata at offset 0x60912 2633 bytes
SHA-256: 27c6d10cfe7974ebf40c1200cc005f9878cc37b7d49ece9cbc396d700c38918a