Malicious RTF — malware analysis report

Static analysis result for SHA-256 1917cd4d19aece44…

MALICIOUS

RTF

327.8 KB First seen: 2021-07-07
MD5: 60e8994cc4dcc877207651e0669e2230 SHA-1: e7484a50f3c5aa3b9db30e9e09c0428a23e4011a SHA-256: 1917cd4d19aece44a8eee760d24c0f0ad862367773f15ad206df09bd355d9328
280 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of malicious OLE object embedding and automatic linking, specifically related to CVE-2017-8570. The document body explicitly instructs the user to 'download the document and click Enable Editing', which is a common lure to bypass security measures. The presence of shellcode command strings and extracted artifacts like 'objdata_01_off00007114.bin' suggests that the file is designed to execute a secondary payload.

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_off00000965.bin rtf-objdata-decoded RTF \objdata at offset 0x965 56425 bytes
SHA-256: c76458bad103e1f9e3b674814895380be20d228c6ca6de51d9a801d8ca86e8e8
objdata_01_off00007114.bin rtf-objdata-decoded RTF \objdata at offset 0x7114 56398 bytes
SHA-256: d75719364695f58cc4c4f794e9a5b799752246b43d03772f4fa6d4e98e9a5233
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): WScript.Shell"")")
objdata_02_off00023bf1.bin rtf-objdata-decoded RTF \objdata at offset 0x23BF1 2632 bytes
SHA-256: a8e170497da15decc11753d202c99c86f7a7ffd2d52481e6b9c79a5403675379
objdata_03_off00025194.bin rtf-objdata-decoded RTF \objdata at offset 0x25194 12297 bytes
SHA-256: e8d4fe950caed6dcfde26f4b616825bbe11b93458425974b7d075167f675abf7