Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 c9bd4a924f08dbae…

MALICIOUS

RTF / .DOC

1.96 MB First seen: 2022-02-15
MD5: 844bd0e7da39179fac9171a0e0491608 SHA-1: 67a15afd1f6f11951b75003ee42fd9dc66fcfedc SHA-256: c9bd4a924f08dbae31a8f1ea813defa8b06f22be01238594a4d1c8be69330f54
180 Risk Score

Malware Insights

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

The file is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_ACTIVATION_RELATED` heuristics strongly indicates this exploit. The `RTF_OBJUPDATE` heuristic suggests that the embedded object is configured to activate automatically. The decoded object data, though truncated, contains what appears to be obfuscated VBScript code, likely intended to download and execute a second-stage payload.

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_off00001347.bin
f2c6bf57cda7aca4db3cdec7c2d476fc6a33e5f68abfdc169a9f5d86b47998e9		 rtf-objdata-decoded RTF \objdata at offset 0x1347 25604 bytes
objdata_01_off0001955a.bin
689965aaaf88dfda2c46136e8ee45ccbdf5d380abcba88d5f9ff529d3c59ced2		 rtf-objdata-decoded RTF \objdata at offset 0x1955A 463381 bytes

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