Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 e00ebcfccf9d1f31…

MALICIOUS

RTF / .DOC

36.8 KB First seen: 2023-02-16
MD5: 2df4ff10911ff942b7ca2ee5e589ea9d SHA-1: 28f61b20bfa99916e21f84724e2a4137408c3785 SHA-256: e00ebcfccf9d1f31703ded64125ecf056e90081a98f75dca8e3437ebbce4bb64
220 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1059.005 PowerShell

The sample is an RTF document that leverages the CVE-2017-11882 vulnerability in Microsoft Equation Editor. The presence of \objdata and \objupdate directives, along with a split ProgID, strongly indicates exploitation of this known flaw. The document body contains a lure to enable editing, common for macro-based malware delivery. The exploitation is likely intended to download and execute a secondary payload.

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_off000040bb.bin
d218fedac829c258436dd0714e771fbeb8cbce85385bf8e91ccc40050569f7e7		 rtf-objdata-decoded RTF \objdata at offset 0x40BB 1723 bytes

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