Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0fb70e15a622bd64…

MALICIOUS

RTF / .DOC

18.1 KB First seen: 2022-08-22
MD5: eb86b585243e71c8459bc792702503e6 SHA-1: 61d2f4c0897aa1303b6fce153300d493c395cc31 SHA-256: 0fb70e15a622bd640e54454988f5e44b52468a1aba67458a0006f7cfa9548a51
160 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1566 Phishing T1059 Command and Scripting Interpreter T1027 Obfuscated Files or Information

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in the Equation Editor. The presence of `RTF_OBJDATA`, `RTF_OBJEMB`, and `CVE_2017_11882` heuristics strongly indicates exploitation of this known vulnerability. The `SE_ENABLE_LURE` heuristic suggests the document attempts to trick the user into enabling editing, a common tactic for macro-based malware or exploits.

Heuristics 5

  • 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 2 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Macro/content-enable lure medium SE_ENABLE_LURE
    Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00001a6e.bin
d60b7329f9c0ec2692765bb66d461a299d4e54cbc15229482c65485f4b8dc2fa
rtf-objdata-decoded RTF \objdata at offset 0x1A6E 3756 bytes