Malicious PDF — malware analysis report

Static analysis result for SHA-256 257b533789685dee…

MALICIOUS

PDF

87.0 KB Created: 2021-09-16 17:27:22 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 81ace7965a00d4133515f929c3d4dde7 SHA-1: 4d02389c0ce07ea2005258d39406868cc525f980 SHA-256: 257b533789685deecc6d0e55eb925fdb14103e6bdb9e2058a05543a3e83abae7
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Static analysis revealed it functions as a link farm, containing numerous URLs pointing to other PDF files hosted on various domains, some of which appear to be compromised CMS uploads. The primary purpose seems to be redirecting users to potentially malicious content, aligning with phishing or malware distribution tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://transmar.biz/ckfinder/userfiles/files/2624483177.pdf In PDF document text
    • http://puntolinea.org/userfiles/files/vojepulibixeri.pdfIn PDF document text
    • http://khiensa.com/UserFiles/File/busuretasudameteguxeb.pdfIn PDF document text
    • http://e-park.es/img/uploads/files/2928892396.pdfIn PDF document text
    • http://innotack.com/userfiles/files/37816718449.pdfIn PDF document text
    • http://longthinhphat.net/uploads/files/mixikadata.pdfIn PDF document text
    • http://studiotecnicoarduini.eu/userfiles/files/79992706505.pdfIn PDF document text
    • http://tion.hu/upload/file/78732965064.pdfIn PDF document text
    • http://pansophers.com/wp-content/plugins/formcraft/file-upload/server/content/files/161432a27bc938---nipazajewufukobusutadalo.pdfIn PDF document text
    • http://dohertylaw.net/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/tiridofakuguvopof.pdfIn PDF document text
    • https://eownauto.com/uploadpic/files/21008482873.pdfIn PDF document text
    • http://qunjl.com/userfiles/files/bowajisino.pdfIn PDF document text
    • https://leuphuotcamap.com/uploads/image/files/81166500675.pdfIn PDF document text
    • http://indyskischool.com/ckfinder/userfiles/files/tavusipanunibanoberig.pdfIn PDF document text
    • https://aguiapromocional.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613a6f7180482---8417096474.pdfIn PDF document text
    • https://mimpi1pusat.com/contents/files/vujeja.pdfIn PDF document text
    • https://xetnghiemadndanang.com/upload/userfiles/files/47698963873.pdfIn PDF document text
    • http://studiogaleazzo.eu/userfiles/files/pivosoma.pdfIn PDF document text
    • http://slowjamsundays.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b19864c8c8---vajafutezesuza.pdfIn PDF document text
    • https://astoraccessories.com/uploads/ckfinder/files/xakijuwo.pdfIn PDF document text
    • https://gionggiacam.gagiongvitgiong.com/ckfinder/userfiles/files/xegume.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/1f9bdb1899be729888225b09b8e5914c/kinude.pdfIn PDF document text
    • https://doanhnghiepvietnam.niengiamdoanhnghiep.vn/img_duhoc/files/38376769820.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=codes+for+fortnite+skins+2021PDF 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_off0000f160.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF160 10556 bytes
SHA-256: 86833a291da2ce0e8a2b4a1f756cac239d60c6ed04edb149d18f5a58a36ddaf5
font_01_sfnt_off000109a9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x109A9 17596 bytes
SHA-256: c34af95a2b131a417e680a6d2943a021cdda1f02fdd6846802f3957deec404ff
font_02_sfnt_off00013672.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13672 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1