Malicious PDF — malware analysis report

Static analysis result for SHA-256 51e7b3a21da0a001…

MALICIOUS

PDF

81.3 KB Created: 2021-09-09 10:31:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 1f344ad1cb9cd23d85ef2af30954730e SHA-1: e4b354571600608469d5ecaf9cf1527dd49bf10a SHA-256: 51e7b3a21da0a001f2792382beb22ad94ed6666959edfb47eba68b89b9900702
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier. It contains numerous embedded URLs that form a link farm, pointing to other PDF files hosted on various domains, many of which are flagged as compromised or disposable. This suggests a phishing or malware distribution campaign where the initial PDF acts as a lure to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://banquat.com/userfiles/files/32804710672.pdf In PDF document text
    • https://sanmuabancongty.vn/images/content/files/gosorinajare.pdfIn PDF document text
    • https://agriplan-rs.com/dados/ckfinder/files/budatizomozulusukav.pdfIn PDF document text
    • https://nordiskvillaventilation.dk/userfiles/file/xinuvovinomisojerukaji.pdfIn PDF document text
    • http://crabandclaw.com/uploads/files/fakofidaxamewotudagi.pdfIn PDF document text
    • http://www.morrisjones.co.uk/EditorImages/file/71727557306.pdfIn PDF document text
    • http://benetworkingpro.com/ckfinder/userfiles/files/zumino.pdfIn PDF document text
    • http://ecompletecontact.com/ckfinder/userfiles/files/mesafedozarudemarin.pdfIn PDF document text
    • http://01host.ru/userfiles/files/72535083088.pdfIn PDF document text
    • https://forexinc.ca/upload/editor/file/19289922335.pdfIn PDF document text
    • http://www.moyekolodin.com/files/futemuvozulodavope.pdfIn PDF document text
    • https://ambalatender.com/upload/files/71164548329.pdfIn PDF document text
    • https://yellowmangocafe.com/userfiles/file/14319023948.pdfIn PDF document text
    • https://adetexfoamgroup.centralcms.cloud/galeria/files/migapesila.pdfIn PDF document text
    • http://covina.crazyrockinsushi.com/uploads/files/11234261831.pdfIn PDF document text
    • http://all-paca.com/ckeditor/ckfinder/core/connector/php/uploads/files/50505332888.pdfIn PDF document text
    • https://autoroman-service.ro/imagini_ws/1401890551.pdfIn PDF document text
    • http://top1np.com/ckfinder/userfiles/files/vusidumejogor.pdfIn PDF document text
    • https://www.femregenx.co.za/wp-content/plugins/super-forms/uploads/php/files/9p1g7dnjgrvsjo3r9ba54mqd07/tadofadofixixu.pdfIn PDF document text
    • https://brylka-kfz.de/wp-content/plugins/formcraft/file-upload/server/content/files/1612ffbf71359d---vutugomujikalawafilajufa.pdfIn PDF document text
    • http://az4group.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/16132b5fed2946---tonutulekowibokaxawemari.pdfIn PDF document text
    • https://2ruoteexpo.it/ckfinder/userfiles/files/retelon.pdfIn PDF document text
    • http://ambulatorioveterinariovianello.eu/userfiles/files/diragirovodedefira.pdfIn PDF document text
    • http://sts-logistika.ru/wp-content/plugins/super-forms/uploads/php/files/a554dc8a9d1864b0576e67ce9c584eb9/91273190935.pdfIn PDF document text
    • https://goldmenu.com/userfiles/file/novivasonibajekeset.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=how+to+know+redmi+phone+modelPDF 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_off0000da7d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA7D 10496 bytes
SHA-256: 24dea1047938ce053819c2d987f20030ac6ab59427d77554038189751901afa7
font_01_sfnt_off0000f210.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF210 17664 bytes
SHA-256: 662c1b77695047c0ac7fbff065258b9e5fc69de91a6bcbe2124825045c835be9
font_02_sfnt_off00011f80.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F80 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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