Malicious RTF / .DOC — malware analysis report

Static analysis result for SHA-256 5d299e9984704364…

MALICIOUS

RTF / .DOC

10.4 KB
MD5: 957a5c203041bc25338033dbd4945966 SHA-1: 15bd84e78b6735f98f8b346791c7824f76e63184 SHA-256: 5d299e99847043640d9d67634e9d608846445d571d7ad97267b9d9ec1156e19e
180 Risk Score

Malware Insights

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

The sample is an RTF document that contains an embedded OLE object. Heuristics indicate the exploitation of CVE-2017-11882 via Microsoft Equation Editor, which is a common method for arbitrary code execution. The document body is heavily obfuscated and does not provide direct clues to the payload's intent, but the exploit itself is the primary indicator of malicious activity.

Heuristics 5

  • Obfuscated Equation Editor ProgID + activation critical CVE related RTF_EQUATION_EDITOR
    RTF decodes to an Equation.3 ProgID from top-level \objdata hex after nested RTF junk groups are ignored, and the document also contains \objemb plus \objupdate activation. This is an obfuscated Equation Editor exploit surface associated with CVE-2017-11882 / CVE-2018-0802 families, but no exact malformed MTEF CVE primitive was recovered from this object.
  • 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.
  • \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_off00001238.bin
17dafb2fb8878e05188fb9681e3166d7321bed9938b6ecade6f2600e465af2c0		 rtf-objdata-decoded RTF \objdata at offset 0x1238 1887 bytes

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