RTF malware analysis — malicious · 20db65160dc9b3e7

MALICIOUS

RTF

323.7 KB Authoring application: Riched20 6.3.9600 First seen: 2018-02-19

MD5: 721d6b11a645d524b4361a21d6ca6ad5 SHA-1: 677cd1ecf154ee967c7b0af35c89f0b2fa225bb9 SHA-256: 20db65160dc9b3e721fc7903a706d012695a2b67877b74842e7b063899ef7b5d

462 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of exploitation, most critically the CVE-2017-11882 vulnerability in Equation Editor. This vulnerability allows for arbitrary code execution when the embedded OLE object is activated. The presence of PE headers in hex data and suspicious extracted artifacts further confirm the malicious nature of the file, likely delivered as a spearphishing attachment.

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: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
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.
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://ocsp.usertrust.com0 In RTF body
- https://secure.comodo.net/CPS0FIn RTF body
- http://ocsp.comodoca.com0In RTF body
- http://www.usertrust.com1In RTF body
- http://crl.usertrust.com/AddTrustExternalCARoot.crl05In RTF body
- http://crl.comodoca.com/COMODOSHA256CodeSigningCA.crl0wIn RTF body
- http://crt.comodoca.com/COMODOSHA256CodeSigningCA.crt0$In RTF body
- http://crl.usertrust.com/UTN-USERFirst-Object.crl05In RTF body
- https://www.chiark.greenend.org.uk/~sgtatham/putty/0In RTF body

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000000ef.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xEF	157291 bytes
SHA-256: `c0c70728c3ff90995b50365a8422b2f35ac61cfe01c6602b05721221ce069fd7`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.90, consistent with packed or encrypted content.
`objdata_01_off0004ce14.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x4CE14	3980 bytes
SHA-256: `8fcf3eea2fa18b5c37fb769bdeec2b7936cc0b411158dab84a1f44a750fe02c5`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\ifu.exe &��D$,f-Q��%
`objdata_02_off0004f05a.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x4F05A	3546 bytes
SHA-256: `1b16f7080b3585765d8a399ff6c25b3f37031180161d8cb60077958f877f1d5d`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\ifu.exe AC

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