Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 12ae20280553510c…

MALICIOUS

RTF / .DOC

1.73 MB First seen: 2022-04-08
MD5: d50e949e4e1368f2f635834f98d3c54e SHA-1: b3f7f30dc4367a53733cc96903acce69408959d3 SHA-256: 12ae20280553510c7e5e5da3920eb56b3dabf5c732cf657342809b8b5fc2d98b
340 Risk Score

Malware Insights

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

The sample is an RTF document containing embedded OLE objects, specifically triggering heuristics related to Equation Editor exploits and OLE activation. The critical ClamAV detection confirms it as Rtf.Exploit.CVE_2017_11882-6584355-1, indicating exploitation of a known vulnerability for client execution. The large amount of hex-encoded data within the OLE object suggests it is used to hide a secondary payload.

Heuristics 8

  • 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.
  • 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
  • ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
  • 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1807KB 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_off00000fb9.bin
e144e1bfb6e63d947cfe27f05cb58b2c1b0a2bc726de354efa1517e18997fa2a
rtf-objdata-decoded RTF \objdata at offset 0xFB9 903739 bytes