RTF malware analysis — malicious · 4e1a2f731688f9aa

MALICIOUS

RTF

935.9 KB Created: 2018-02-22 20:08:00 First seen: 2020-02-04

MD5: 46d91a91ecdf9c0abc7355c4e7cf08fc SHA-1: 21e5a2ca34f97e0fd8c36534c5fba3f274c698fc SHA-256: 4e1a2f731688f9aab80b1f55d9101bb1cddec08214d4379621c434899a01efbf

322 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The sample is an RTF document containing an embedded OLE object that exploits the Equation Editor vulnerability (CVE-2017-11882). This vulnerability allows for the execution of arbitrary code upon activation of the embedded object, likely leading to the download and execution of a secondary payload. The presence of ClamAV detection for 'Doc.Exploit.Cve_2017_11882-7570663-1' further confirms 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
Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED

RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact attribution was not recovered.
ClamAV: Doc.Exploit.Cve_2017_11882-7570663-1 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Doc.Exploit.Cve_2017_11882-7570663-1
\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.
Package object class high RTF_OBJCLASS_PACKAGE

OLE Package object — can wrap arbitrary files
OLE object data medium RTF_OBJDATA

RTF contains 3 \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.
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 http://schemas.microsoft.com/office/word/2003/wordml In RTF body

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000078d0.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x78D0	453872 bytes
SHA-256: `758816af480f5400b88a343f1bbe62b48e6cbd89ac6d0d6a51e1750296c034cb`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 8.00, consistent with packed or encrypted content.
`objdata_01_off000e52e6.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xE52E6	9781 bytes
SHA-256: `20f8b7ac964442c1266cca393e812ee31197416f72cdd9335aa9f521a415db00`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis found candidate code region(s). Indicators: SC_GETPC_CALL, SC_STR_VIRTUALPROTECT Static shellcode analysis recovered API/import strings: VirtualAlloc, VirtualAllocEx, VirtualProtect, VirtualProtectEx, WriteProcessMemory, ReadProcessMemory
`objdata_02_off000e52f8.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xE52F8	35 bytes
SHA-256: `1188b98b21f50564ab8b476f25b6deab999a2f58a56c4dd0daa0f5883cfa941d`

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