Malicious RTF — malware analysis report

Static analysis result for SHA-256 cf09bb95c5963933…

MALICIOUS

RTF

17.0 KB First seen: 2019-11-20
MD5: cdb09781e3a2b4f66158871fbe8f78a9 SHA-1: 4c50fda4f951bb3e3727c6dadbd965b0effb8632 SHA-256: cf09bb95c5963933338ef0da0ff427024ac2b66a0feca91da50e5cfa58c5c82f
200 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 triggers a critical vulnerability, CVE-2017-11882, related to Microsoft Equation Editor. This exploit allows for arbitrary code execution, which is typically used to download and run a second-stage malicious payload. The presence of the ".objupdate" directive further indicates an attempt to force OLE activation.

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_off00001f59.bin rtf-objdata-decoded RTF \objdata at offset 0x1F59 4666 bytes
SHA-256: 1a221bc2bd197745da3a681c828e5a372c0f0f65ff9fae0a4888314993ed02af