Malicious RTF — malware analysis report

Static analysis result for SHA-256 c8c36a325a18b4fa…

MALICIOUS

RTF

28.2 KB First seen: 2018-11-20
MD5: 44e462c0d90789420b4a530e19c2f1ab SHA-1: 094754c17c219cb17ec112dc4d49c7d2a92d04ad SHA-256: c8c36a325a18b4faddc98d282b16b10b0a568526979eafcd8327e5ac77b0bb18
200 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object. Critical heuristics indicate the exploitation of CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. This exploit allows for arbitrary code execution, which is typically used to download and execute a second-stage payload. The ClamAV detection name further corroborates the exploit's presence.

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.
  • ClamAV: Doc.Exploit.CVE_2017_11882-6934206-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Doc.Exploit.CVE_2017_11882-6934206-0
  • \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_off0000003a.bin rtf-objdata-decoded RTF \objdata at offset 0x3A 4142 bytes
SHA-256: c272b318657bd9335bf74a6bd1ef09aa88d17d491cb4348ebbb61fafa6943975