Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 7f0f3941419dd02e…

MALICIOUS

RTF / .DOC

1.81 MB First seen: 2022-03-29
MD5: 1bcb6dfac243f6fcab671fa93c14dc7d SHA-1: 3db5a9391a8962c7467acce9b0e0c82afaa70d59 SHA-256: 7f0f3941419dd02e82dc168fd0e2d56e07a86e584cad9b6472d028eefb66007b
300 Risk Score

Malware Insights

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

The sample is an RTF document containing multiple indicators of exploitation for CVE-2017-11882, specifically related to the Equation Editor. Heuristics indicate the presence of OLE objects, excessive hex data, and composite monikers, all consistent with this exploit. ClamAV also explicitly detects it as Rtf.Exploit.CVE_2017_11882-6584355-1, strongly suggesting the exploit's purpose is to achieve code execution, likely for a secondary payload download.

Heuristics 7

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • 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
  • \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 ~1896KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000125a.bin rtf-objdata-decoded RTF \objdata at offset 0x125A 948306 bytes
SHA-256: 9026daf442c686210777a2ff64fa8f32aaaf21a30c847cb174cc82c59b1c0d25