Malicious RTF — malware analysis report

Static analysis result for SHA-256 c7af7cf902d55ec5…

MALICIOUS

RTF

7.2 KB First seen: 2019-04-18
MD5: 5491598ab4a98674243dd3b333b22189 SHA-1: 7b62644b1c833812dbbb4350ee32f52631e0b5f1 SHA-256: c7af7cf902d55ec5836af22ccf2230c4e29d655c97d35cb8bc093e47dc9ac1b2
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 Equation Editor (CVE-2017-11882) is being exploited. This exploit allows for arbitrary code execution, likely to download and run a secondary payload. The file is identified as malicious by ClamAV with a signature matching 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_off0000003c.bin rtf-objdata-decoded RTF \objdata at offset 0x3C 3633 bytes
SHA-256: 81752d71fcd5891a531c537ce7cad3ee2a7da04b5a774691f0bd0eba989003a2