RTF malware analysis — malicious · 1c8cfccd2e45ea89

MALICIOUS

RTF

18.2 KB First seen: 2022-10-20

MD5: b9b672f41346a7e134e9ee07c25cde86 SHA-1: 42e3ded330cc4a1b6b96357eba0e0a00402439ec SHA-256: 1c8cfccd2e45ea898125a62686ee97a1e923dfbbc8652889027d46b04aa5dc75

240 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File

The RTF document contains an embedded OLE object specifically identified as an Equation Editor object, which is a known vector for exploiting CVE-2017-11882. The presence of `RTF_EQUATION_EDITOR` and `CVE_2017_11882_EQUATION_OLE10NATIVE` heuristics strongly indicates this vulnerability is being leveraged. The ` tf_objupdate` heuristic suggests the embedded object is designed to be activated automatically, likely to execute a secondary payload.

Heuristics 6

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.
Equation Editor CLSID critical RTF_EQUATION_EDITOR

Equation Editor OLE CLSID found inside an OLE object — exploited by CVE-2017-11882 / CVE-2018-0802 / CVE-2018-0798
\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

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00001544.bin` `02f523734f080a10ba97e6c10896ac9e3f6397110692547bef8b5f3772a58b20`	rtf-objdata-decoded	RTF \objdata at offset 0x1544	3670 bytes

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