Malicious PDF — malware analysis report

Static analysis result for SHA-256 0f81d56a7a4e2c43…

MALICIOUS

PDF

79.3 KB Created: 2021-09-10 13:37:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: a3754a9421cde89aa48509b6d0491935 SHA-1: be43b4835f178313cd2c721d304d68333c49a8ee SHA-256: 0f81d56a7a4e2c4320d27cf6434343637e8ef7cc3bfa27dcee5df76b3d45fd7e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. It functions as a link farm, containing numerous embedded URLs pointing to external PDF files hosted on various domains. This pattern is commonly used for phishing or distributing further malware. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' specifically flags the document's structure as a link farm on disposable hosting.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • 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://buffinvestment.com/upload/ckfinder/files/81458981179.pdf In PDF document text
    • http://annamsaigonlaw.com/upload/files/jopilemowilopixuzowewasat.pdfIn PDF document text
    • https://deesudcoolingtower.com/userfiles/file/88174699344.pdfIn PDF document text
    • http://ampletrekking.com/userfiles/file/2667029253.pdfIn PDF document text
    • http://erfaspot.com/resimler/files/5778258619.pdfIn PDF document text
    • https://jakspravnenapsa.cz/userfiles/file/legikitewinufisewafura.pdfIn PDF document text
    • http://www.letnifestiwal.pl/ckfinder/userfiles/files/48390859519.pdfIn PDF document text
    • http://321eastern-thailand.com/userfiles/files/durexesowaxurozekimawim.pdfIn PDF document text
    • https://triangle-electronics.com/assets/userfiles/file/xelolabojodovizowepilup.pdfIn PDF document text
    • https://editora-arara-azul.com.br/site/admin/ckfinder/userfiles/files/79579915366.pdfIn PDF document text
    • http://studioagm.it/userfiles/files/sanesepu.pdfIn PDF document text
    • http://balade-pierry.fr/userfiles/file/98786126447.pdfIn PDF document text
    • http://denprokhorov.ru/images/file/dutusatejotabezudisigabo.pdfIn PDF document text
    • http://apart1day.ru/file/73380916479.pdfIn PDF document text
    • http://yavuzselimvakfi.org/resimler/site/files/bafelanitena.pdfIn PDF document text
    • http://tomgiongvip.com/uploads/files/file/zorobowovunipasojapatuv.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/161370532c8664---pemeka.pdfIn PDF document text
    • http://worldofpacifiers.com/editor_uploads/system/files/tiligedawez.pdfIn PDF document text
    • http://sendedianqi.com/upload_fck/file/2021-9-9/20210909033650155297.pdfIn PDF document text
    • http://interface-referencement.com/userfiles/file/xifisoniduw.pdfIn PDF document text
    • http://mazraeir.com/images/upload/files/59241706892.pdfIn PDF document text
    • https://vieclamlaocai.vn/webroot/img/files/wakinu.pdfIn PDF document text
    • http://satunatc.ac.th/ckfinder/userfiles/files/wejul.pdfIn PDF document text
    • https://fivetc.vn/uploads/files/winepi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/3CAf4wW3hvY/uplcv?utm_term=online+fraction+reducerPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d298.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD298 10424 bytes
SHA-256: d121383e0417bce36ad70f97bb3e77324b87ce350ae2da079605e378cf1d2fe9
font_01_sfnt_off0000ea58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA58 17672 bytes
SHA-256: df8ab00248f7626e097780ab7afe682f5aa6e5710ce685859f57f568e3b8ecbf
font_02_sfnt_off000117dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1