RTF malware analysis — malicious · d1c042300c3dc280

MALICIOUS

RTF

134.5 KB First seen: 2019-01-12

MD5: b936568ff3cf7d5c5edb074cf1416884 SHA-1: 4dc2f89482bf5ce3ab43396da3eaa6c37bc8001e SHA-256: d1c042300c3dc280989304ee1bd571d9725321f24d37373f1032e0803c0a2b06

360 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains critical heuristics indicating the exploitation of CVE-2017-11882 via the Equation Editor OLE object. This vulnerability allows for arbitrary code execution when the document is opened. The presence of OLE object data and specific CLSIDs strongly suggests this exploit vector.

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

Heap-spray pattern detected high SC_HEAP_SPRAY

Repeated 0x04 bytes found

Disassembly

Attempted x86 opcode disassembly

00000038  0404              add al, 4
0000003A  0404              add al, 4
0000003C  0404              add al, 4
0000003E  0404              add al, 4
00000040  0404              add al, 4
00000042  0404              add al, 4
00000044  0404              add al, 4
00000046  0404              add al, 4
00000048  0404              add al, 4
0000004A  0404              add al, 4
0000004C  0404              add al, 4
0000004E  0404              add al, 4
00000050  0404              add al, 4
00000052  0404              add al, 4
00000054  0404              add al, 4
00000056  0404              add al, 4
00000058  0404              add al, 4
0000005A  0404              add al, 4
0000005C  0404              add al, 4
0000005E  0404              add al, 4
00000060  0404              add al, 4
00000062  0404              add al, 4
00000064  0404              add al, 4
00000066  0404              add al, 4
00000068  0404              add al, 4
0000006A  0404              add al, 4
0000006C  0404              add al, 4
0000006E  0404              add al, 4
00000070  0404              add al, 4
00000072  0404              add al, 4
00000074  0404              add al, 4
00000076  0404              add al, 4
00000078  0404              add al, 4
0000007A  0404              add al, 4
0000007C  0404              add al, 4
0000007E  0404              add al, 4
00000080  0404              add al, 4
00000082  0404              add al, 4
00000084  0404              add al, 4
00000086  0404              add al, 4
00000088  0404              add al, 4
0000008A  0404              add al, 4
0000008C  0404              add al, 4
0000008E  0404              add al, 4
00000090  0404              add al, 4
00000092  0404              add al, 4
00000094  0404              add al, 4
00000096  0404              add al, 4

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_off000045e1.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x45E1	42064 bytes
SHA-256: `4cf55555f022b280547c22c883e13391aca7ac2fb810f0992b836de20044b8f7`

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