Malicious RTF — malware analysis report

Static analysis result for SHA-256 a77bf5af7368885d…

MALICIOUS

RTF

15.1 KB First seen: 2019-01-12
MD5: c5738458188828c8093db8e52d2d98b4 SHA-1: 65829ad83c45d1e67e352d0c2649e797260a84f3 SHA-256: a77bf5af7368885dcad1be3ac50d4e52abf9be365c75f1b604a0791d870d3716
240 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 exploits the CVE-2017-11882 vulnerability in the Equation Editor. This vulnerability is known to be used to execute arbitrary code, typically to download and run a second-stage payload. The ClamAV detection confirms the presence of this exploit.

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.
  • 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

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000017c7.bin rtf-objdata-decoded RTF \objdata at offset 0x17C7 4662 bytes
SHA-256: d1377c94c786e76f421c296fcda61dffe0e9548518759154fc713898a8d1db65