Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 814c0adabb8c02a1…

MALICIOUS

RTF / .DOC

3.9 KB First seen: 2023-01-16
MD5: ca6c4002a04afc18e521613910f9002f SHA-1: 5b2fca47fe09a3768079ea3ec4605195dc037e37 SHA-256: 814c0adabb8c02a1c6d8d6bc2f2eca6d3e6069a1b15e22f838387e11965087b1
180 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution

The RTF file contains an embedded OLE object that triggers CVE-2017-11882 through the Equation Editor. This exploit is known to allow for arbitrary code execution, likely to download and run a second-stage payload. The specific object activation and ProgID point directly to this known vulnerability.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED
    RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
  • \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_off00000075.bin
79c2b980d87aa700cd4921163e59edf99de8e51c667400e12495acd522d33c3e
rtf-objdata-decoded RTF \objdata at offset 0x75 1884 bytes