Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 ea68f30ae2c118cc…

MALICIOUS

RTF / .DOC

18.7 KB First seen: 2022-08-23
MD5: 0ca5d606fcf4c2ccaacaad11974b74cf SHA-1: 64425f1f653908f313ab2853fe465fa0000653ea SHA-256: ea68f30ae2c118cc614eb14f3bea9144ab790cfba6e39a38eeb56b1b900483ab
140 Risk Score

Malware Insights

MITRE ATT&CK
T1204 Malicious Link T1204.002 Malicious Link: Malicious File T1059 Command and Scripting Interpreter T1059.005 Command and Scripting Interpreter: Visual Basic T1566 Phishing T1566.001 Phishing: Spearphishing Attachment

The sample is an RTF document that exploits CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of OLE object data and an \objupdate directive strongly suggests an attempt to trigger code execution. The document body contains a lure instructing the user to 'enable editing', a common tactic for macro-based malware.

Heuristics 4

  • 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
  • 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_off0000177c.bin
b3743b423f80b68955f26a3117dcc91620b27452569c359ea2e09932db979f58
rtf-objdata-decoded RTF \objdata at offset 0x177C 4253 bytes