RTF malware analysis — malicious · 7aaca4d5c7f143eb

MALICIOUS

RTF

66.3 KB Authoring application: riched20 6.3.9600 First seen: 2019-01-20

MD5: bcb350c254d394f2f80eec6d6dd8eb10 SHA-1: 2d0832af535608d52935cbc261d856f182370d4d SHA-256: 7aaca4d5c7f143eb39f92804fd383aa2cfba2ecaf84010bad700547c31a1c5ab

340 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of the CVE-2017-11882 exploit, specifically related to the Equation Editor object. This vulnerability allows for the execution of arbitrary code, likely to download and run a secondary payload. The presence of OLE object data and the specific ClamAV detection further confirm the malicious nature of the file.

Heuristics 8

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
\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
Suspicious extracted artifact medium 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.

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	33458 bytes
SHA-256: `f6311568ebb4297b7ee7e634bed0061c0074fd8a5016beaa31943345a7a983d8`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis found candidate code region(s). Indicators: NOP sled, SC_PEB_ACCESS, SC_PEB_ACCESS

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