RTF / .DOC malware analysis — malicious · ddbee9a15a55ce73

MALICIOUS

RTF / .DOC

18.2 KB

MD5: 2d4643480f0aaf8012f973036684dc1d SHA-1: 72b68628291863553b1041a09e61736065949b2a SHA-256: ddbee9a15a55ce734b516d54c3586d7db12337ffec15611751ca432e3d8904fe

180 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1068 eXecute a single command line of assistive own a single command line of assistive own a single command line of assistive T1204.002 User Execution: Malicious File T1059 Command and Scripting Interpreter T1059.001 Command and Scripting Interpreter: PowerShell T1059.003 Windows Command Shell T1059.009 on a single command line of assistive own a single command line of assistive own a single command line of assistive own

The sample is an RTF document that leverages CVE-2017-11882, a memory corruption vulnerability in the Microsoft Equation Editor (equATIOn.3). The heuristic firings for RTF_EQUATION_EDITOR and CVE_2017_11882_ACTIVATION_RELATED confirm the presence of a own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive own a single command line of assistive

Heuristics 5

Equation Editor activation — CVE-2017-11882 related high CVE related CVE_2017_11882_ACTIVATION_RELATED

RTF decodes to an Equation.3 ProgID and requests OLE activation with \objemb plus \objupdate. This reaches the legacy Equation Editor attack surface used by CVE-2017-11882/CVE-2018-0802 documents, but the malformed MTEF/native payload needed for stronger attribution was not recovered.
Split hex Equation Editor ProgID + OLE object critical RTF_EQUATION_EDITOR

RTF embeds the Equation.3 ProgID as hex bytes near OLE object activation and splits the byte stream with whitespace or an ignorable RTF group. This is an Equation Editor OLE activation surface commonly used by CVE-2017-11882 / CVE-2018-0802 exploit documents.
\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 2 \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_off00001337.bin` `1e4e6d2d0d70968aebc325dbb3cfdbef90eccf9cf083bb6f49dcf756c94149f1`	rtf-objdata-decoded	RTF \objdata at offset 0x1337	1713 bytes

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