Malicious PDF — malware analysis report

Static analysis result for SHA-256 31336cf5258c630b…

MALICIOUS

PDF

75.8 KB Created: 2021-09-18 22:10:48 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6aaca70be3f4fc92567da6b1a8888a52 SHA-1: f51892fb020ca5c09b7e9f27ba964f8d3fb11ba1 SHA-256: 31336cf5258c630b7d2e29a7560165a065339e3e3501e89ebd22df9d52c8a889
156 Risk Score

Malware Insights

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

The PDF document was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous embedded URLs pointing to various external sites, some hosted on compromised CMS uploads or disposable domains. The primary purpose appears to be directing users to potentially malicious content or phishing pages.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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 http://coeb.eu/userfiles/files/zonibi.pdf In PDF document text
    • https://mygrind.ie/userfiles/file/7933158521.pdfIn PDF document text
    • http://ansatrans.ru/admin/ckfinder/userfiles/files/fekapem.pdfIn PDF document text
    • http://solar-makernavi.com/ckfinder/userfiles/files/rakorarofet.pdfIn PDF document text
    • http://farashimirooz.com/files/89999854217.pdfIn PDF document text
    • https://fuze-pay.com/ckfinder/userfiles/files/64785488146.pdfIn PDF document text
    • https://eduinfinite.com/wp-content/plugins/super-forms/uploads/php/files/e841bc663fc6a183031ec75afdbbd148/kilewozubor.pdfIn PDF document text
    • http://www.cavice.fi/tiedostot/files/dexonotowixamaxi.pdfIn PDF document text
    • http://normel.org/files/upload/file/zefab.pdfIn PDF document text
    • http://ipmarketing.net/FCKeditor/editor/filemanager/connectors/userfiles/file/meteparugaxufekatajiwupu.pdfIn PDF document text
    • https://12shio1.com/contents/files/45087461024.pdfIn PDF document text
    • https://postelezmasivu-ostrava.cz/ckfinder/userfiles/files/22798083122.pdfIn PDF document text
    • https://misbahelmudii.org/ckfinder/userfiles/files/jageposaboboxosus.pdfIn PDF document text
    • http://biemmecommerciale.eu/userfiles/files/diwojizorifomal.pdfIn PDF document text
    • https://redac.ch/upload/55905621498.pdfIn PDF document text
    • http://markfarolaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/mupugerubetevupewiw.pdfIn PDF document text
    • http://synphabase.ch/upload/file/16407059514.pdfIn PDF document text
    • http://campfirewtx.org/userfiles/file/15820377070.pdfIn PDF document text
    • http://corkpotters.com/images/sanojuvenuwekoseburinuf.pdfIn PDF document text
    • http://dental-forum.ru/userfiles/file/tulul.pdfIn PDF document text
    • http://elrey-uslugi.ru/media/file/tuzimetukasebepajetafipen.pdfIn PDF document text
    • https://stcatherine.ac.ug/wp-content/plugins/formcraft/file-upload/server/content/files/16142e9784a342---74589883105.pdfIn PDF document text
    • https://ost-fogging.com/upload/files/fagozosunesaxiv.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/161410f783cdad---fepunikaxerufedevuwog.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/PmAiG5ZyT-k/uplcv?utm_term=mario+flash+5PDF 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_off0000bff2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBFF2 20140 bytes
SHA-256: da776911033cf771e52c741f4eb4f3a3d8fb4da63ca9696510273daf456b3536
font_01_sfnt_off0000f2da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2DA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010af1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10AF1 10104 bytes
SHA-256: ee0a95aae3843cbee6d7bf9fc1d376c0aba2ad2e7d1be48f56eda417c4c6f8df