RTF malware analysis — malicious · 5abf32efa91887e9

MALICIOUS

RTF

28.5 KB First seen: 2022-11-18

MD5: fb0e1a97296d00d6d8feb3596ee21da4 SHA-1: ba92b937504613aea312cbdb6557601d9d8c6b36 SHA-256: 5abf32efa91887e95aaf49b4ee0b152de460e3cc77015a46c2ae2f8c6a4411fd

220 Risk Score

Malware Insights

MITRE ATT&CK

T1566.001 Spearphishing Attachment T1204.002 Malicious File T1059.005 Visual Basic

The RTF document contains an embedded OLE object specifically identified as related to CVE-2017-11882, a known vulnerability in Microsoft Equation Editor. The presence of RTF_OBJDATA, RTF_OBJAUTLINK, and RTF_EQUATION_EDITOR heuristics strongly indicates an attempt to exploit this vulnerability. The SE_ENABLE_LURE heuristic suggests the document prompts the user to enable editing, a common social engineering tactic to facilitate the exploit. The primary goal is to leverage this exploit to download and execute a secondary payload.

Heuristics 6

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.
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
Macro/content-enable lure medium SE_ENABLE_LURE

Document instructs the user to enable macros or editing — a common technique used by malware droppers to bypass Office macro security settings

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off0000584a.bin` `28f21466cf3ef485e5c1aafd619a4d091bcb2932b1301d3fd38d5e76c00cfbcc`	rtf-objdata-decoded	RTF \objdata at offset 0x584A	1435 bytes

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