Malicious PDF — malware analysis report

Static analysis result for SHA-256 91b3352520110c6c…

MALICIOUS

PDF

85.6 KB Created: 2021-07-03 09:56:24 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 33ddaa21e604a646489388eab517452b SHA-1: ba8b446ce8c436cabfadf8922f84729e695f0c14 SHA-256: 91b3352520110c6cd6bcf5e5d1a548b9cbcd92b25c762d4de8dc334e83ce54d3
156 Risk Score

Malware Insights

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

The sample is identified as malicious by ML classifiers and ClamAV, indicating it's a phishing or trojan PDF. It functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, likely for SEO poisoning or to redirect users to malicious sites. No scripts were extracted, but the PDF structure and URL patterns suggest an attempt to lure users to external, potentially harmful, content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9972

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 https://prtl.pl/userfiles/file/94407053896.pdf In PDF document text
    • http://www.highlandmetals.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/160a0137ea891b---74818863820.pdfIn PDF document text
    • https://fceresources.com/ckfinder/userfiles/files/kavaforeniwe.pdfIn PDF document text
    • https://www.audioclinica.pt/wp-content/plugins/super-forms/uploads/php/files/aciqm5bc402sd2151fpqcqk8bp/45219071050.pdfIn PDF document text
    • http://teamwork-poetschke.com/ckfinder/userfiles/files/xabazabusidizejopu.pdfIn PDF document text
    • http://koopmankennedyfeller.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/24933114730.pdfIn PDF document text
    • http://worksafeorg.com/wp-content/plugins/super-forms/uploads/php/files/gf1kkqe6vvhhjaj5mkglignek2/45458330541.pdfIn PDF document text
    • http://all4pets.cz/ckfinder/userfiles/files/61224722114.pdfIn PDF document text
    • https://k-kompany.ru/wp-content/plugins/super-forms/uploads/php/files/7cbf2deaccbf0c6b100d96212f437655/96336850740.pdfIn PDF document text
    • http://www.linkkorea.co.kr/wp-content/plugins/formcraft/file-upload/server/content/files/160b06a9eb2768---8331679241.pdfIn PDF document text
    • http://microcement.ua/userfiles/file/31334595820.pdfIn PDF document text
    • https://www.couleurs-et-jardin.fr/wp-content/plugins/formcraft/file-upload/server/content/files/16094e7fdd1386---morirositirixurevoma.pdfIn PDF document text
    • https://lightsourceindiana.com/wp-content/plugins/super-forms/uploads/php/files/61423851c9850c6a7946dc4ae5fe1c80/16468271148.pdfIn PDF document text
    • https://rittenhousesmiles.com/wp-content/plugins/super-forms/uploads/php/files/aeb4e219381f20b17b708efea32ac6d7/gajodasupezubezumami.pdfIn PDF document text
    • http://2girlstrippin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aa979cf23ea---musawisuju.pdfIn PDF document text
    • http://rolmech-strzelno.pl/Upload/file/36376710024.pdfIn PDF document text
    • http://www.etoiles-recrutement.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cbb5eef0f76---50905173286.pdfIn PDF document text
    • https://mygamedaysports.com/wp-content/plugins/super-forms/uploads/php/files/5d40cfdd324ca3523095d0628d8d3089/sejovojukedowarojekavomej.pdfIn PDF document text
    • https://web-sila.ru/wp-content/plugins/super-forms/uploads/php/files/3d193df11378a9b62e6f5d1d4113a388/dukobiwuromozezagex.pdfIn PDF document text
    • https://accesoriosalmayor.com/images/userfiles/file/sodebunubepixuletigit.pdfIn PDF document text
    • http://www.sunargrup.com.tr/wp-content/plugins/super-forms/uploads/php/files/6ju0l4m2a074dpvueaht96kqg5/753623979.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/Om9ozkHLxGw/uplcv?utm_term=10th+class+maths+1st+lesson+real+numbersPDF 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_off0000e8d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8D5 17396 bytes
SHA-256: f6d9a14097a4d2359ead455a42698aa241a50b90c82a2fa3d135a0292fb916a0
font_01_sfnt_off000116d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x116D4 10720 bytes
SHA-256: 0a029e3796a7c2e5eeec48fc8be190e36f9cabb10cb6f60a08ae0f9c67c84829
font_02_sfnt_off00012f4f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12F4F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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