Malicious RTF — malware analysis report

Static analysis result for SHA-256 b572c0ef43dd6c8e…

MALICIOUS

RTF

2.16 MB
MD5: 055f989314852d0768d03996e60a2465 SHA-1: 6aa4678646ed12594132cbcec0093f0c6058c563 SHA-256: b572c0ef43dd6c8e6fda9cdba2adb7ab8dfe074981d62d582d8457ae3f96c7f9
220 Risk Score

Malware Insights

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

The RTF file contains OLE object data, specifically related to Equation Editor, which is a strong indicator of the CVE-2017-11882 vulnerability. This vulnerability is known to be exploited for client execution, likely to download and run a second-stage payload. The presence of large, hex-encoded data blocks within the OLE object further suggests the hiding of a malicious payload.

Heuristics 5

  • Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED
    RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2259KB of hex-encoded data inside \objdata sections — may hide a payload
  • OLE object data medium RTF_OBJDATA
    RTF contains 2 \objdata section(s) — embedded OLE objects

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000ef.bin
bf513770af95e6afa6db1ede6ddbb878a0f48979a8dd804349b7546f2968701b		 rtf-objdata-decoded RTF \objdata at offset 0xEF 903886 bytes

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