RTF malware analysis — malicious · 88b27afe0dfce43c

MALICIOUS

RTF

7.1 KB First seen: 2018-08-14

MD5: 436658cc2282a22f0c6e9780803e2457 SHA-1: fafcc0ad25b608d31a2b1833b8838323cf6f3a76 SHA-256: 88b27afe0dfce43cf996ca7994d78a4ac9b5d72e3f439e81ae526a52ad499e01

340 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

This RTF document contains an embedded OLE object that exploits the CVE-2017-11882 vulnerability in Microsoft Equation Editor. The heuristic firings strongly indicate the presence of a malicious payload within the Ole10Native stream, designed for client-side code execution. The file is classified as malicious due to this exploit, and it is likely used as a delivery mechanism for further malicious activity.

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
Equation Editor Ole10Native payload — CVE-2017-11882 likely critical CVE likely CVE_2017_11882_EQUATION_OLE10NATIVE

RTF decodes to an activated Microsoft Equation 3.0 OLE storage whose payload is a high-entropy Ole10Native stream rather than normal Equation Native/MTEF data. This is a weaponized Equation Editor RCE delivery shape consistent with CVE-2017-11882/CVE-2018-0802.
Ole10Native stream in RTF OLE object high CVE related RTF_OLE10NATIVE_STREAM

RTF contains an embedded OLE object with an Ole10Native stream. This is a strong payload-container signal and is related to Word/OLE exploit delivery, but it is not specific enough on its own to assign a CVE.
ClamAV: Rtf.Exploit.CVE_2017_11882-6584355-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Exploit.CVE_2017_11882-6584355-1
Automatically linked OLE object high RTF_OBJAUTLINK

RTF contains \objautlink — an automatically linked OLE object surface that can be updated or activated when Word opens the document.
\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
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_off0000003f.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x3F	3625 bytes
SHA-256: `e8931adeec579dd53d550e9a6c3555249673f03ee2f8e527aa48907bb5a556ad`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis found candidate code region(s). Indicators: SC_GETPC_CALL

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