Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9b6b5ca4e669be8…

MALICIOUS

PDF

88.3 KB Created: 2021-08-06 10:44:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 36ca9301898caac87a5c62fd865d416b SHA-1: d69a3631ddeeb893dfd7cca6840d145fbb2a3eb8 SHA-256: a9b6b5ca4e669be8c43644588cf8f160d72a833cf5b75f9baa1391ddd0803a35
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous embedded URLs that point to compromised CMS upload directories, specifically WordPress formcraft plugin uploads. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a vehicle for these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160fe0ef972567---fesefivinag.pdf In PDF document text
    • http://dream-mebel.com/pic/file/tenid.pdfIn PDF document text
    • http://brezov-gaj.si/uporabnik/file/koguko.pdfIn PDF document text
    • http://www.makattakasinti.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f5e1616d49---40063640159.pdfIn PDF document text
    • http://littlepearlbooks.in/data/eimages/file/58926805185.pdfIn PDF document text
    • http://hungthanhauto.com/luutru/files/77986071203.pdfIn PDF document text
    • http://www.ddd-iasi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160e0f18345e94---kavumipizesulon.pdfIn PDF document text
    • https://kltccompany.com/ckfinder/userfiles/files/gilobitamivukulesix.pdfIn PDF document text
    • http://carrollcountylawyers.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/17248781860.pdfIn PDF document text
    • https://anctools.com/ckfinder/userfiles/files/gasijalitiwokivobanun.pdfIn PDF document text
    • http://zvezda-rostov.ru/ckfinder/userfiles/files/bababo.pdfIn PDF document text
    • http://www.onekaddy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b07f36be664---rajezusasapakedo.pdfIn PDF document text
    • https://www.acptechnologies.com/wp-content/plugins/formcraft/file-upload/server/content/files/160add6c0e8ec4---dalugu.pdfIn PDF document text
    • http://csss77.com/clients/d/df/df7f2fdc42e243c7a03c192a8228c0be/File/81809612056.pdfIn PDF document text
    • https://www.taxiserviceh24.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bac44db44b3---liwevaxefajekesipul.pdfIn PDF document text
    • https://giolog.biz/images/bulk_images/files/tedavetepalebutanirido.pdfIn PDF document text
    • http://mazurubezpieczenia.pl/zdjecia/fck/file/5377921428.pdfIn PDF document text
    • https://realestateconnect.biz/wp-content/plugins/super-forms/uploads/php/files/7cku2b92hhe0sa3a6vdnmte5a6/gamobavuvusututepurufik.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad72bfaef9a---vukivonubatimukoja.pdfIn PDF document text
    • https://sk-developers.com/wp-content/plugins/formcraft/file-upload/server/content/files/16078aec7299d1---wejoxezugogatok.pdfIn PDF document text
    • https://sieompaysdebray.fr/lesiom/txt/imgadmin/file/15769051974.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/ngfLrbzwjls/uplcv?utm_term=what%27s+the+process+of+vulcanizationPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ee3a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE3A 16780 bytes
SHA-256: 93fb49c2a174d1e0bbd8d69707b498e0791c8dc8cbc89a3dbb939811cc11163f
font_01_sfnt_off000119be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119BE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000131cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x131CB 1736 bytes
SHA-256: a970dc50f3fc642965faeb3d6f2817be39c8fee70eb220fb851f6e1b0fd382ad
font_03_sfnt_off00013a10.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A10 10832 bytes
SHA-256: b8eacee4e449de8d993928a280d289f21b4ba5ff1fda39a624ab410f2ddc8cf9

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