Malicious RTF — malware analysis report

Static analysis result for SHA-256 898ca1bf0f6a4114…

MALICIOUS

RTF

289.6 KB First seen: 2019-04-18
MD5: 8dfb316b05f8b7f768814b0c1e58afe1 SHA-1: 2d5ae74ae43bb371f60f5b9b47aed26e1dddd533 SHA-256: 898ca1bf0f6a4114a8d660935829491acfc29b72cc01a54215025f63d4df8656
220 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 triggering heuristics related to the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for arbitrary code execution, which is the primary mechanism for this attack. The ClamAV detection name further confirms the exploit. The attack pattern is consistent with a malicious attachment delivered via spearphishing, aiming to exploit this known vulnerability to gain initial execution.

Heuristics 5

  • 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
  • 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
  • \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_off0000d17b.bin rtf-objdata-decoded RTF \objdata at offset 0xD17B 76949 bytes
SHA-256: f7fdea003c9248317e976e3c5c74ad063a139f18ff6dd1118926f4510454453e