Win.Dropper.Tspy-6671875-0 RTF malware analysis — malicious · dcceb121af8cc77d

MALICIOUS

RTF

1.14 MB First seen: 2018-10-07

MD5: 66fd8100f5b15c985d9a6c62e5a14271 SHA-1: 094e439d8926268f8f3e223b3ade2e214a0ac028 SHA-256: dcceb121af8cc77db00e45f58506490478f8fd96f29ff3f9b5e1e519c8ca9165

540 Risk Score

Malware Insights

Win.Dropper.Tspy-6671875-0 · confidence 95%

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains embedded OLE objects, specifically exploiting the CVE-2017-11882 vulnerability in Equation Editor. This exploit likely facilitates the execution of a secondary payload, as indicated by the detection of shellcode and PE headers within the extracted OLE data. The document body also contains a lure to enable editing, further supporting its role as a malicious dropper.

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.
ClamAV: Win.Dropper.Tspy-6671875-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Win.Dropper.Tspy-6671875-0
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 ~1174KB 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.
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000080.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x80	587010 bytes
SHA-256: `08b3c624388422b00299d5fe545d6c9543068282cd9428e8c63266d538363d7b`
Detection ClamAV: Win.Dropper.Tspy-6671875-0 Obfuscation or payload: likely Static shellcode analysis found candidate code region(s). Indicators: SC_MSF_REVERSE, SC_STR_VIRTUALALLOC, SC_STR_LOADLIBRARY Static shellcode analysis recovered API/import strings: LoadLibraryExA, VirtualAlloc, GetProcAddress, ExitProcess, LoadLibraryA, VirtualProtect
`objdata_01_off0011eaf0.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x11EAF0	4207 bytes
SHA-256: `ef261d9f8116954c855beea1f17e96d35048b856921b138ce9fce4082bde5283`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\Windowscj.exe &��D$,f-Q��%
`objdata_02_off001213b3.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x1213B3	3773 bytes
SHA-256: `d56865408244d503d4903631e8628a686c9f27862bc7a6517ed630d945e1511f`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\Windowscj.exe AC

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