Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 713dd2b4e0370c60…

MALICIOUS

RTF / .DOC

1.69 MB First seen: 2022-03-22
MD5: b9c3e0ea061821bfa4a9eefcd121e873 SHA-1: bdc5d048a8df1b3b4caf8c5e10b7d9d5c7d7b858 SHA-256: 713dd2b4e0370c6012c444e763f5f7d285d346ce3d4f0e1cd2755187353d0449
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 critical heuristics for Equation Editor exploitation (CVE-2017-11882). The presence of large amounts of hex-encoded data within the OLE object suggests it is likely hiding a malicious payload. The ClamAV detection ID further confirms the exploit targeting CVE-2017-11882, which is commonly used to achieve arbitrary code execution.

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 ~1768KB 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_off00001dbf.bin
df9c9cc3b27dcfc493274cce3e8a9ac07e716e436ac6e6aaa4c45d51ffdf1444
rtf-objdata-decoded RTF \objdata at offset 0x1DBF 884289 bytes