Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 b41f7133924702f8…

MALICIOUS

RTF / .DOC

4.2 KB
MD5: 834f146cf5ddf4972bf12437bf1a2c0d SHA-1: 7d953cb68bb28cdf13cd60557f191449745a6cea SHA-256: b41f7133924702f8e2562f7b180bd6df806bad3498339220631cd1effb6884d6
180 Risk Score

Malware Insights

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

The sample is an RTF document containing an embedded Equation.3 object and the \objupdate control word, which is a characteristic pattern for CVE-2017-11882 and CVE-2018-0802 exploits. No scripts were extracted from this sample, but the structural evidence strongly indicates an attempt to trigger a memory corruption vulnerability in the legacy Equation Editor. The lack of a recovered MTEF stream prevents a specific malware family attribution.

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_off000000ce.bin
36df8f4b5599c6ae1c2acd8c9441693efa4fed431aca184969807afc8c9d630f		 rtf-objdata-decoded RTF \objdata at offset 0xCE 1852 bytes

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