Malicious RTF — malware analysis report

Static analysis result for SHA-256 a62da0d5420e9391…

MALICIOUS

RTF

4.78 MB Created: 2024-04-03 08:46:00 First seen: 2025-04-07
MD5: ed027631f34210ee9334362a09270d7d SHA-1: ffb25c14fa29f14adec73ed8171fbdf2f02876c7 SHA-256: a62da0d5420e9391a8693a9217dd8d1a22cb42ef5d8887cbb2199a69b4d7ada2
222 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1105 Ingress Tool Transfer

The RTF file contains multiple indicators of exploitation for CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of OLE objects, specifically within the Equation Editor's ProgID, and the use of \objupdate strongly suggest this exploit is being leveraged. The large amount of hex-encoded data within the OLE objects likely hides a secondary payload, which is commonly used to download and execute further malicious content.

Heuristics 7

  • 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.
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2817KB 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
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://schemas.microsoft.com/office/word/2003/wordml

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00003a12.bin
8868a1d8b5a434bcdb100086d1a3e08f334aac93e674c767539564f179c49efb		 rtf-objdata-decoded RTF \objdata at offset 0x3A12 1420905 bytes
objdata_01_off002c4737.bin
cfdb4a077c5f246e92e6322395cebc5a3dcf8a28c92ec8882aadb5231c9a8a69		 rtf-objdata-decoded RTF \objdata at offset 0x2C4737 584266 bytes

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