Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 63367911d4082d43…

MALICIOUS

RTF / .DOC

1.53 MB First seen: 2022-03-28
MD5: 848a3777471bc172c51cbbdb0a4ea65f SHA-1: 502520d8924d9e537ca8bf0210fe455e458a6c4b SHA-256: 63367911d4082d43bdc707a024f3ede1e3ca59006bf95efa4de26b0e333129cd
340 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains multiple indicators of exploitation, including OLE object data, automatic linking, and a critical finding for the Equation Editor CLSID, strongly suggesting exploitation of CVE-2017-11882. ClamAV also explicitly detected this CVE. The large amount of hex-encoded data within the OLE object likely hides the malicious payload. While no scripts were directly extracted, the nature of the exploit implies a download and execution of a second-stage 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 ~1603KB 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_off00001241.bin
661be8b409af889f000864851165717703019f0204b15e5adb26fe016a0a0b94
rtf-objdata-decoded RTF \objdata at offset 0x1241 801867 bytes