RTF malware analysis — malicious · 13ce56581c8ad851

MALICIOUS

RTF

8.1 KB First seen: 2019-05-16

MD5: db2753547014f36d7422b6a59330c7ad SHA-1: 33cf192bc6691188262fc663ae094ad3de24d263 SHA-256: 13ce56581c8ad851fc44ad6c6789829e7c250b2c8af465c4a163b9a28c9b8a41

320 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 leverages the Equation Editor vulnerability (CVE-2017-11882). This exploit is known to facilitate arbitrary code execution, typically used to download and run a secondary malicious payload. The presence of the Equation Editor CLSID and Ole10Native stream strongly indicates this exploit.

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
\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_off0000003b.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x3B	4140 bytes
SHA-256: `6a3823971c166d5dcd7cf0ec401778aac8150495ee17f3f2db30f8ed6a538b1a`
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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