Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 0a11de20075af87c…

MALICIOUS

RTF / .DOC

4.3 KB First seen: 2022-07-04
MD5: fc093d735945f60a730542bac679fe59 SHA-1: c86fdd24057f9be925d6753ca0887755a9712df3 SHA-256: 0a11de20075af87c4a9e8bb7fbce3751c8d8890f15c2a9665e5ce18d972404c3
180 Risk Score

Malware Insights

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

The RTF file contains heuristics indicating the exploitation of CVE-2017-11882 through an embedded Equation Editor object. This exploit is commonly used to deliver malicious payloads. The presence of the 'eqUaTion.3' ProgID strongly suggests this vulnerability is being leveraged for arbitrary code execution.

Heuristics 5

  • 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.
  • \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
  • 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_off000000a5.bin
b7a3a20f1c9247faacee65edfc7898f191aa9bb71aebcd8a1418ce5042eb8a8e
rtf-objdata-decoded RTF \objdata at offset 0xA5 1798 bytes