Malicious RTF — malware analysis report

Static analysis result for SHA-256 b3e032224cebdcb5…

MALICIOUS

RTF

641.0 KB Authoring application: Riched20 6.3.9600 First seen: 2018-07-27
MD5: 526ec4eb1c7efa2fdc28934e1765ebf1 SHA-1: 1e22922936451d2ca85593d4ea948d11e7c34085 SHA-256: b3e032224cebdcb5e9841f3ea792550671920b71256d69ef2eb3fcc40a927f02
480 Risk Score

Malware Insights

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

The RTF file contains multiple indicators of malicious activity, most critically the exploitation of CVE-2017-11882 through an embedded Equation Editor object. This vulnerability is known to be used for arbitrary code execution. The presence of PE headers in hex data and ClamAV detections for Agent and Dropper families further confirm its malicious nature, suggesting it acts as a dropper for further malicious payloads.

Heuristics 10

  • Equation Editor CLSID critical CVE likely RTF_EQUATION_EDITOR
    Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
  • CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882
    Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
  • ClamAV: Win.Malware.Qakbot-9941434-1 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Qakbot-9941434-1
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • \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.
  • Package object class high RTF_OBJCLASS_PACKAGE
    OLE Package object — can wrap arbitrary files
  • Suspicious extracted artifact high EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • OLE object data medium RTF_OBJDATA
    RTF contains 3 \objdata section(s) — embedded OLE objects
  • Embedded OLE object medium RTF_OBJEMB
    RTF contains \objemb — embedded OLE object
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000ef.bin rtf-objdata-decoded RTF \objdata at offset 0xEF 319719 bytes
SHA-256: 2841c5760eb7d06afae40c26e73fc1d4255ec8b8e2e7bcc7907a12557c9ea398
Detection
ClamAV: Win.Malware.Qakbot-9941434-1
Obfuscation or payload: likely
Carved artifact entropy is 7.89, consistent with packed or encrypted content.
objdata_01_off0009c30c.bin rtf-objdata-decoded RTF \objdata at offset 0x9C30C 3980 bytes
SHA-256: 11ca699483e12f8cd3ab5086ff33f47f903aa35ebc48f64e5d2167f4eabd4855
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\Window.exe &��D$,f-Q���%
objdata_02_off0009e552.bin rtf-objdata-decoded RTF \objdata at offset 0x9E552 3546 bytes
SHA-256: 7b73e254edc9c8dad8f0df44c67e659e3fc95e6378796a78f85d09033e932374
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\Window.exe A C