Malicious RTF — malware analysis report

Static analysis result for SHA-256 51660f486318d7f0…

MALICIOUS

RTF

14.7 KB First seen: 2019-09-30
MD5: 58624ad080b747e87a319d0c6cc8ee5b SHA-1: 44a0585e6759b89b8154cf03dd98ea4c54e2719c SHA-256: 51660f486318d7f024b7738a1833a10b483792373b51cc705191a7398b017971
260 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 object data, specifically targeting the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code when the OLE object is activated. The presence of RTF_EQUATION_EDITOR and CVE_2017_11882_EQUATION_OLE10NATIVE heuristics strongly indicates exploitation of this known vulnerability for client execution.

Heuristics 6

  • 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.
  • 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_off0000189d.bin rtf-objdata-decoded RTF \objdata at offset 0x189D 4153 bytes
SHA-256: e33e6c13aec2bcbbda0d44fae3f49093827447bb4679bd3168d2f092d29dd8f8

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