Malicious RTF — malware analysis report

Static analysis result for SHA-256 6c8db93724abc230…

MALICIOUS

RTF

461.0 KB First seen: 2021-06-13
MD5: d17e1a36a90b076c20c0411fab4178da SHA-1: 42396f7f2bf2aea5aa9b3b5702f348677f385f6b SHA-256: 6c8db93724abc23040cfd448caf6eb801d080433b1770b67c5629c538ffc670c
280 Risk Score

Malware Insights

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

The RTF file contains multiple OLE objects, including composite monikers, and triggers ".objupdate" which are indicative of exploitation attempts. Specifically, the CVE-2017-8570 heuristic indicates the file is designed to drop and execute a script. The embedded artifact objdata_01_off0000735b.bin is flagged as a suspicious extracted artifact containing shellcode command strings.

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.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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 4 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00000bac.bin rtf-objdata-decoded RTF \objdata at offset 0xBAC 121694 bytes
SHA-256: 631235a12f24e398ebc03ab87566a50759d3b94fc18782f685395f38bb133081
objdata_01_off0000735b.bin rtf-objdata-decoded RTF \objdata at offset 0x735B 121667 bytes
SHA-256: 4dff656067b6a97c67fe2afab73194410aa2da0b20de42604168134cd9497dc4
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off00045086.bin rtf-objdata-decoded RTF \objdata at offset 0x45086 2632 bytes
SHA-256: 32e8e449cdc043249ce37c79c9eaf2af80a02cb8175718a8a0ce726d961b7d16
objdata_03_off00046629.bin rtf-objdata-decoded RTF \objdata at offset 0x46629 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7