Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 fd3bb2e73250ea4e…

MALICIOUS

RTF / .DOC

2.05 MB First seen: 2022-04-27
MD5: a0285ae10926d4c39a11d6400e508154 SHA-1: 2ad085ea77758da4470793278a24c26c75e54ffe SHA-256: fd3bb2e73250ea4ee8ed754cb05a64751b7955a4ee4fde96259d0aa7d487c654
180 Risk Score

Malware Insights

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

The RTF document contains an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The decoded object contains VBA code that appears to be designed to download and execute a second-stage payload. The presence of `Equation.3` as a ProgID strongly indicates the use of this specific vulnerability.

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 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000012ab.bin
bb619d76dcb4fd8a92a3402dd5c354853d04f2d569ec1b15ba1ae41c187b5ab8		 rtf-objdata-decoded RTF \objdata at offset 0x12AB 86017 bytes
objdata_01_off00036c1c.bin
15b7f137c999929be510fea7aaa1c34a11c506a87bc2b1d42d45986f1d905f44		 rtf-objdata-decoded RTF \objdata at offset 0x36C1C 457432 bytes

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