Malicious RTF — malware analysis report

Static analysis result for SHA-256 04fffe52f93084dc…

MALICIOUS

RTF

5.44 MB First seen: 2023-03-18
MD5: bcb9dddc3a3c81e74a45cd2d2ddf7b5f SHA-1: 78cf832b7d8b741296c599748fddd2bd075335cb SHA-256: 04fffe52f93084dc3da76743e96951e7c09a872b4cbed9e4eff6d41851416d50
300 Risk Score

Malware Insights

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

The sample is an RTF document containing a critical Equation Editor exploit (CVE-2017-11882), as indicated by multiple high and critical heuristic firings and ClamAV detection. The exploit likely facilitates the execution of a secondary payload, which is common for this type of attack. No specific family could be identified, but the attack pattern is consistent with a spearphishing attachment.

Heuristics 7

  • 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.
  • Ole10Native stream in RTF OLE object high CVE related RTF_OLE10NATIVE_STREAM
    RTF contains an embedded OLE object with an Ole10Native stream. This is a strong payload-container signal and is related to Word/OLE exploit delivery, but it is not specific enough on its own to assign a CVE.
  • ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • Equation Editor CLSID critical RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • \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 ~5703KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 1 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000067b.bin rtf-objdata-decoded RTF \objdata at offset 0x67B 2851893 bytes
SHA-256: 93fa305ea34761abb2f07ff6176e0cbbc93f88dd7806aa84ff1771de784fc264