RTF malware analysis — malicious · 2930a61808227bc7

MALICIOUS

RTF

5.12 MB First seen: 2021-05-22

MD5: 7392e36545c92b9d7dcb30746e981bf3 SHA-1: 0b1d9c1c3e8491bc2c3c2acde8e704fcb3e33364 SHA-256: 2930a61808227bc70eaf56896a0c7af419746dd4e3aa4eafc1a1a0e5951c392e

262 Risk Score

Malware Insights

MITRE ATT&CK

T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF document contains critical heuristics indicating the exploitation of CVE-2017-11882 through an embedded OLE object. This exploit is known to download and execute a second-stage payload, which is likely the primary malicious function of this file. The large amount of hex-encoded data within the OLE object further supports the presence of a hidden payload.

Heuristics 7

Equation Editor OLE1 native payload — CVE-2017-11882 related critical CVE related CVE_2017_11882_RELATED

RTF decodes to an OLE1 Equation.3 embedded object whose native data is large and payload-like, and \objupdate requests automatic activation. This is the delivery shape used by Equation Editor RCE documents such as CVE-2017-11882/CVE-2018-0802, but the malformed MTEF record needed for exact 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.
Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX

RTF contains ~5367KB of hex-encoded data inside \objdata sections — may hide a payload
OLE object data medium RTF_OBJDATA

RTF contains 2 \objdata section(s) — embedded OLE objects
Suspicious extracted artifact info 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.

Extracted artifacts 1

Files carved from inside the sample during analysis.

Filename	Kind	Source	Size
`objdata_00_off000000aa.bin`	rtf-objdata-decoded	RTF \objdata at offset 0xAA	2683601 bytes
SHA-256: `0f572bb2c49e4047541aa0936fc78cfa8b9ec771244c21a998494b1bcf6f706c`
Detection ClamAV: No threats found Obfuscation or payload: likely Carved artifact entropy is 7.99, consistent with packed or encrypted content.

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