RTF / .DOC malware analysis — malicious · 28c1ffe0cb33c5b6

MALICIOUS

RTF / .DOC

23.2 KB First seen: 2023-06-13

MD5: df476b115a000832a0d688c512418b64 SHA-1: 74241c8e7f4aa8656d5053077660f6e4c8afb6b8 SHA-256: 28c1ffe0cb33c5b6fdcc5d9352f061ec686e821e7d4346676c5bb702f2361fa3

200 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The sample is an RTF document containing an OLE object that leverages the Equation Editor vulnerability (CVE-2017-11882). This vulnerability is known to be used for initial access, often through malicious documents. The presence of the ".objdata" and ".objupdate" sections, along with the "Ole10Native" stream, strongly indicates the exploitation of this specific CVE. The document body is heavily obfuscated and does not provide clear textual lures, but the technical indicators are sufficient to identify the attack vector.

Heuristics 5

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.
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

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00000adb.bin` `5660141be50f177b7dab3a03457d30d1582a77f9fa4b03ec165f2d3e9d5333f1`	rtf-objdata-decoded	RTF \objdata at offset 0xADB	4193 bytes

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