Malicious RTF — malware analysis report

Static analysis result for SHA-256 b354030c784f7167…

MALICIOUS

RTF

1.54 MB Authoring application: Riched20 6.3.9600 First seen: 2018-03-24
MD5: ed8eabbaa31eff8947be40e865e9b428 SHA-1: 7a69132633955e3bd79aa764be6188df3958bb23 SHA-256: b354030c784f71670d73601c2b985cd02013f969c44ae4d577cae76d441f5739
560 Risk Score

Malware Insights

MITRE ATT&CK
T1203 Exploitation for Client Execution T1566.001 Spearphishing Attachment

The RTF file contains multiple indicators of malicious activity, most critically the exploitation of CVE-2017-11882 via the Equation Editor. This vulnerability allows for arbitrary code execution when the document is opened. The presence of embedded OLE objects and large hex-encoded data blocks further suggests the hiding of a malicious payload, likely a second-stage executable.

Heuristics 12

  • 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-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.
  • Composite Moniker in RTF OLE object high CVE related RTF_COMPOSITE_MONIKER_RELATED
    RTF contains Composite Moniker CLSID in OLE object context, but no nearby scriptlet/SCT payload was confirmed. Treat as related moniker attack-surface evidence rather than proof of CVE-2017-8570 exploitation.
  • ClamAV: Win.Malware.Cvrq-7582330-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Win.Malware.Cvrq-7582330-0
  • PE header (with DOS stub) in hex data critical RTF_MZ_HEX
    Hex-encoded PE (MZ + DOS stub) found inside RTF — likely an embedded executable payload
  • \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
  • Large hex data blocks in OLE object high RTF_EXCESSIVE_HEX
    RTF contains ~1602KB of hex-encoded data inside \objdata sections — may hide a payload
  • Suspicious extracted artifact high 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.
  • 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
  • OlePres presentation stream in RTF OLE object medium RTF_OLEPRES_STREAM
    RTF contains an embedded OLE object with an OlePres presentation stream. OlePres is an OLE presentation marker and is not enough on its own to identify CVE-2025-21298.

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off000000ef.bin rtf-objdata-decoded RTF \objdata at offset 0xEF 801484 bytes
SHA-256: 96932327659863a70199d5a34d76a78884203c20972e556623c56a9d84c01b3f
Detection
ClamAV: Win.Malware.Cvrq-7582330-0
Obfuscation or payload: likely
Static shellcode analysis found candidate code region(s). Indicators: SC_MSF_BIND, SC_MSF_REVERSE, SC_STR_VIRTUALALLOC Static shellcode analysis recovered API/import strings: LoadLibraryExA, VirtualAlloc, GetProcAddress, ExitProcess
objdata_01_off001876d6.bin rtf-objdata-decoded RTF \objdata at offset 0x1876D6 3980 bytes
SHA-256: 78520455b1bc503317819bba33da5d17cad99f7ab2b53f8d977d185fb859f803
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\put.exe &��D$,f-Q���%
objdata_02_off0018991c.bin rtf-objdata-decoded RTF \objdata at offset 0x18991C 3546 bytes
SHA-256: 6fae5f0795333efc630294722a6333ec0dab388558ba36380d0aa014e00d985f
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Static shellcode analysis recovered command string(s): cmd.exe /c%tmp%\put.exe A C