Malicious PDF — malware analysis report

Static analysis result for SHA-256 53a7333ac2d498e1…

MALICIOUS

PDF

79.4 KB Created: 2021-09-11 04:02:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 00aaf4984db7feb87a358f349c60b5b8 SHA-1: 2a0bd79f25cc62d510f32b8dbb3edffc55a5098e SHA-256: 53a7333ac2d498e11381a422eb57083ade9e8079809873bd889273cc1bc8e67a
186 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating malicious intent, including random URL links and being classified as a link farm on disposable hosting. The ML classifier and ClamAV detection strongly suggest this is a phishing or trojan PDF. The primary malicious URL identified is https://childrencareandliteracysociety.org/userfiles/files/gebolivarovupezefux.pdf, which likely serves as a lure for a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9958

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.
  • 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.
  • QR-code redirect lure medium SE_QR_LURE
    Document instructs the user to scan a QR code with a phone — consistent with QR phishing, but also common in legitimate documents
  • 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://childrencareandliteracysociety.org/userfiles/files/gebolivarovupezefux.pdf In PDF document text
    • https://a2designbg.com/userfiles/file/50127981205.pdfIn PDF document text
    • http://gramercy-grand.ru/files/file/71579446279.pdfIn PDF document text
    • https://www.auto-ecole-rive-droite.fr/ckfinder/userfiles/files/48953869073.pdfIn PDF document text
    • http://form4concrete.ru/pics/cont/file/tuvizafela.pdfIn PDF document text
    • http://linker-apps.com/files/20764157344.pdfIn PDF document text
    • http://gaushalango.com/uploaded_files/userfiles/files/64960664528.pdfIn PDF document text
    • https://biocenfis.es/uploads/assets/file/dapoberemominibugiwo.pdfIn PDF document text
    • https://pieseautocomenzi.ro/userfiles/file/mojozuderiruroretasoto.pdfIn PDF document text
    • http://jobsandhi.com/uploaded_files/userfiles/files/44201356200.pdfIn PDF document text
    • https://www.hkha.com.hk/ckfinder/userfiles/files/fidetitile.pdfIn PDF document text
    • http://twinmd.ru/userfiles/file/xoruduzajizax.pdfIn PDF document text
    • http://falconltd.pl/cache/file/67782592304.pdfIn PDF document text
    • http://jainfarms.com/uploads/rabodakezozuxovuzivodesal.pdfIn PDF document text
    • http://vakantie-noordlimburg.nl/ckfinder/userfiles/files/fidemizetubinawatosovav.pdfIn PDF document text
    • https://civilkontroll.hu/uploads/file/99842967656.pdfIn PDF document text
    • http://abwmechanicsville.com/uploads/files/lirawonokugukerekew.pdfIn PDF document text
    • http://ballmillfactory.com/d/files/fajabejat.pdfIn PDF document text
    • http://labotinnghia.com/img/files/23719210555.pdfIn PDF document text
    • https://www.acta-mobilier.fr/ckfinder/userfiles/files/gexenobekuzaf.pdfIn PDF document text
    • http://wildpflanzen-planung.de/file/gajisilatoketipav.pdfIn PDF document text
    • http://deurwater.com/wp-content/plugins/formcraft/file-upload/server/content/files/161309007f379e---gizorisuxopozuji.pdfIn PDF document text
    • http://ji-tien.com/userfiles/file/fitajirifatanojab.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3CAf4wW3hvY/uplcv?utm_term=home+up+android+11PDF 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_off0000d4c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4C5 16992 bytes
SHA-256: fbfee230db38377c8d803734b041e66dcd0712425c5e0bd34d31da411c2aef69
font_01_sfnt_off000100f3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x100F3 10384 bytes
SHA-256: 48f2574d56c400087fa3a7e56e3a4a2913d91189783b8f662aaf53711924d96b
font_02_sfnt_off00011852.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11852 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1