Malicious RTF — malware analysis report

Static analysis result for SHA-256 ab35b2b22718624f…

MALICIOUS

RTF

898.1 KB Created: 2018-11-28 09:56:00 Authoring application: Microsoft Word 11.0.5604 First seen: 2020-05-14
MD5: 45746a0a686750cb9f6775eee63d1f23 SHA-1: 9c0863a0527a5477bc92e50a465f13da9d668442 SHA-256: ab35b2b22718624fcaf1a290b3f138c009469b7449d1a280ec67767ea55b44ae
342 Risk Score

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
  • 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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
objdata_00_off00034896.bin rtf-objdata-decoded RTF \objdata at offset 0x34896 340208 bytes
SHA-256: f72a3d712d7d5ffca15b56be21e7970f1d3ad5a30ac6cd90683c56e94a464350
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact entropy is 7.77, consistent with packed or encrypted content.
objdata_01_off000daaac.bin rtf-objdata-decoded RTF \objdata at offset 0xDAAAC 11842 bytes
SHA-256: 82a0e9d2b46fe974ae1d3298ffd405eb8e6ea8fda7665fef57d4e0d76c604d9d
objdata_02_off000daabe.bin rtf-objdata-decoded RTF \objdata at offset 0xDAABE 35 bytes
SHA-256: d0771b17e6418e479f528fc4aa124822669975a78f8dc3e35cdc4b0f7c212c4e

Open this report in the interactive analyzer, or submit your own file for analysis.