Malicious RTF — malware analysis report

Static analysis result for SHA-256 c93ed79804c8c51c…

MALICIOUS

RTF

9.2 KB First seen: 2018-05-18
MD5: 8fc395c57e008066d71dc761df865b65 SHA-1: a218db5a8f017a7645986ad570bb43969eee3264 SHA-256: c93ed79804c8c51c8389d706df7f9ebf5fe903e18c2919bb365aa273b6ff2989
320 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object with a CLSID indicative of Microsoft Equation Editor. Critical heuristics confirm the presence of a payload likely exploiting CVE-2017-11882, which allows for arbitrary code execution. The file's structure and heuristic firings strongly suggest it is designed to exploit this known vulnerability.

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
  • Equation Editor Ole10Native payload — CVE-2017-11882 likely critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE
    RTF decodes to an activated Microsoft Equation 3.0 OLE storage whose payload is a high-entropy Ole10Native stream rather than normal Equation Native/MTEF data. This is a weaponized Equation Editor RCE delivery shape consistent with CVE-2017-11882/CVE-2018-0802.
  • 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
  • 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.
  • 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_off0000003f.bin rtf-objdata-decoded RTF \objdata at offset 0x3F 4664 bytes
SHA-256: f08e1f006d6d7deb54fafb0469d3a03cdb92b244f715dead02db82deaad7e327

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