Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5d84ff17e26d5af0…

MALICIOUS

RTF / .DOC

39.8 KB First seen: 2023-01-31
MD5: 4e3fda8f3793a830cffef2a69d5732a1 SHA-1: b14b132eea30ce1d6377408669b08bf3c2dead1c SHA-256: 5d84ff17e26d5af0efde25962f29500d7690414f3d35a79006a16a3055a71e7d
220 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document that contains an embedded OLE object specifically identified as being related to CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of RTF_OBJDATA, RTF_OBJAUTLINK, RTF_EQUATION_EDITOR, and RTF_OBJUPDATE heuristics strongly indicates exploitation of this vulnerability. The SE_ENABLE_LURE heuristic suggests the document also contains a social engineering element to trick the user into enabling content, which is a common delivery method for exploits.

Heuristics 6

  • 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.
  • Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR
    RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
  • Automatically linked OLE object high RTF_OBJAUTLINK
    RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
  • \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
  • 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_off00005216.bin
7108e059c2ebcd7ba574669aab6cdd50cfb33fefd0f25cf20e1f926bce216d54		 rtf-objdata-decoded RTF \objdata at offset 0x5216 1636 bytes

Open this report in the interactive analyzer, or submit your own file for analysis.