RTF malware analysis — malicious · 9be6d671dd901326

MALICIOUS

RTF

224.4 KB Created: 2018-12-19 04:37:00 First seen: 2019-11-20

MD5: a94db3001c0c3fa3cf40bc7fdf9d21b7 SHA-1: 93211e3e2aa0f97423f5a2e48e03b0c3ef84a431 SHA-256: 9be6d671dd901326fc834296fbd2ed015d64e6037e83d8d1d08a9dcdc107cb33

342 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains multiple critical heuristic firings indicating exploitation of Equation Editor vulnerabilities, specifically CVE-2017-11882 and CVE-2018-0798. These vulnerabilities are commonly exploited to achieve arbitrary code execution. The presence of OLE object data and activation triggers further supports this attack vector. The document body discusses geopolitical news, likely serving as a lure.

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
CVE-2018-0798 — Equation Editor Matrix record overflow critical CVE exact CVE_2018_0798

RTF contains hex-encoded MTEF Matrix record exploit signature (NOP-sled 0x60 + padding 0x61 + return address 0x0BFB). CVE-2018-0798 exploits a stack buffer overflow in EQNEDT32.EXE's Matrix record parser and affected Equation Editor broadly, including builds patched for CVE-2017-11882. Widely used by APT groups (Conimes, KeyBoy, Emissary Panda, Rancor).
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.
ClamAV: Rtf.Exploit.CVE_2018_0802-6825822-0 critical CLAMAV_DETECTION

ClamAV detected this file as malware: Rtf.Exploit.CVE_2018_0802-6825822-0
\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
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 https://ikon.mn/n/1etx In RTF body
- https://www.upi.com/Top_News/World-News/2018/12/05/Mongolia-prime-minister-to-visit-Japan-to-discuss-North-Korea-report-says/1371544024431/?rc_fifo=1In RTF body
- https://www.upi.com/Top_News/World-News/2018/12/05/Mongolia-prime-minister-to-visit-Japan-to-discuss-In RTF body
- https://www.japantimes.co.jp/news/2018/10/19/national/politics-diplomacy/japan-north-korea-intelligence-officials-held-secret-meeting-october-mongolia/In RTF body
- https://www.japantimes.co.jp/news/2018/10/19/national/politics-diplomacy/jIn RTF body
- http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 3

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off00011e0b.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x11E0B	66288 bytes
SHA-256: `9d578dd8da8f145f7ff71adeaab70b4a3191c9d125ad41d84d0d415c40501ba0`
`objdata_01_off00032421.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x32421	11842 bytes
SHA-256: `82a0e9d2b46fe974ae1d3298ffd405eb8e6ea8fda7665fef57d4e0d76c604d9d`
`objdata_02_off00032433.bin`	rtf-objdata-decoded	RTF \objdata at offset 0x32433	35 bytes
SHA-256: `d0771b17e6418e479f528fc4aa124822669975a78f8dc3e35cdc4b0f7c212c4e`

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