Malicious RTF — malware analysis report

Static analysis result for SHA-256 4e9bc336be1115bb…

MALICIOUS

RTF

8.4 KB First seen: 2020-05-25
MD5: 31fa978dc1d4903cd86280858a6987e1 SHA-1: 9100eb5d3df8058b8bdedfc1270bb65cae3a3dc1 SHA-256: 4e9bc336be1115bb9ccaf35c583715d57dbabe0b8f39f7b8fa825c63e9663f5d
200 Risk Score

Malware Insights

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

The RTF file contains embedded OLE object data, specifically triggering the critical CVE-2017-11882 vulnerability related to the Equation Editor. This exploit allows for arbitrary code execution on the victim's machine. The presence of ".objupdate" further indicates an attempt to force the activation of this embedded object. Given the nature of the exploit, it is highly likely this file was delivered as a spearphishing attachment.

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.
  • \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_off00000032.bin rtf-objdata-decoded RTF \objdata at offset 0x32 4152 bytes
SHA-256: 2d20234bc4ddfa3e0a5bcecdcc9bc41dfd4929bae49500849c3793e599cbb164