Malicious RTF — malware analysis report

Static analysis result for SHA-256 dcf152411afddea6…

MALICIOUS

RTF

2.08 MB Authoring application: Riched20 6.3.9600 First seen: 2018-06-25
MD5: 221c1d8087db46124bee5ce3b185f072 SHA-1: 87b66a851491bda8d83dbc4b7e9feec4a0c16baa SHA-256: dcf152411afddea6a4ba1402671ba81bff265da448ee1db2368676b7cdc98acd
560 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 via the Equation Editor. This vulnerability allows for arbitrary code execution when the document is opened. The presence of embedded OLE objects and large hex-encoded data blocks further suggests the hiding of a malicious payload, likely a second-stage executable.

Heuristics 12

  • 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.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • ClamAV: Win.Packed.ImminentMonitorRAT-10019612-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Packed.ImminentMonitorRAT-10019612-0
  • 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
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~2161KB of hex-encoded data inside \objdata sections — may hide a payload
  • 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 1080524 bytes
SHA-256: ff1fe57f935b1074f558fc08802d54b7ae49db0a955ba66c5a1932c9411ea96c
Detection
ClamAV: Win.Packed.ImminentMonitorRAT-10019612-0
Obfuscation or payload: likely
Carved artifact entropy is 7.70, consistent with packed or encrypted content.
objdata_01_off0020fad6.bin rtf-objdata-decoded RTF \objdata at offset 0x20FAD6 3980 bytes
SHA-256: 73fe58abdcceac68cf5656ccc736b4e71714be035a03baf7a93d8ab100b4310b
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\tip.exe &��D$,f-Q���%
objdata_02_off00211d1c.bin rtf-objdata-decoded RTF \objdata at offset 0x211D1C 3546 bytes
SHA-256: e39c627bb32fe47bd1e2422b2aafc5fd8b855d3d8a2f2379aeada470dc242134
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\tip.exe A C