Malicious RTF — malware analysis report

Static analysis result for SHA-256 2d4fcae1b3ebc5dd…

MALICIOUS

RTF

9.2 KB First seen: 2018-10-26
MD5: 0c9b3bb78da62c401dc955b13d591f45 SHA-1: c76ede8ca4c35b28fee494b399bcf2d9fb0745ae SHA-256: 2d4fcae1b3ebc5dd1f7246877720d1fe21ca297523bca137cc532efe647866fc
260 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains an embedded OLE object that leverages a known vulnerability in Microsoft Equation Editor (CVE-2017-11882). This exploit allows for arbitrary code execution when the document is opened, likely leading to the download and execution of a secondary payload. The file's structure and the critical heuristic firings strongly indicate exploitation of this specific vulnerability.

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
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003b.bin rtf-objdata-decoded RTF \objdata at offset 0x3B 4660 bytes
SHA-256: 86d504ca252d426a5f2a03cc2e1a338cab1b166276f0cc04c8eabc6bcd4a579b