Malicious RTF — malware analysis report

Static analysis result for SHA-256 f55216b0f52a81f1…

MALICIOUS

RTF

8.2 KB First seen: 2018-11-13
MD5: e4e3ab0796b7fc4ed568b873408143b8 SHA-1: b098f5a2fafecbb06f5ccea3261d3e64b3f2f6b9 SHA-256: f55216b0f52a81f194d272c70fb497cc1cdcd821997447d94f75de9f72bddd74
240 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object. Heuristics indicate a critical vulnerability in Microsoft Equation Editor (CVE-2017-11882) is being exploited. This vulnerability allows for arbitrary code execution when the document is opened, likely leading to the download and execution of a secondary payload. The file is classified as malicious due to this exploit.

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
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off0000003a.bin rtf-objdata-decoded RTF \objdata at offset 0x3A 4142 bytes
SHA-256: b0b5186b3f68fe3fa4ac2c927182827525b82df361d7dfaf9531e968934b0d60