Malicious PDF — malware analysis report

Static analysis result for SHA-256 4f5a05c9b39c0d51…

MALICIOUS

PDF

81.0 KB Created: 2021-09-09 10:56:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 78586f0bf611ee5c3674d3c0f87de6c4 SHA-1: 7b33b70baa69095c75be76092978fb28f5c0e065 SHA-256: 4f5a05c9b39c0d517480265853db859f6ccbe35e1337eee14480b1456fb63228
186 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to external PDF files, many hosted on disposable domains, suggesting a link farm designed to obscure malicious downloads. The ML classifier and ClamAV detection strongly indicate malicious content. While no scripts were directly extracted, the PDF structure and link farm behavior are indicative of a phishing or malware distribution attempt, likely using embedded JavaScript for obfuscation or redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

Heuristics 7

  • 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 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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://huntic.ru/uplcv?utm_term=come+installare+due+app+uguali+su+android PDF link annotation
    • http://soles2walk.com/data/file/vovirixuwafepilu.pdfIn PDF document text
    • http://zimmerei-possert.at/wotisofotidabemarobupofa.pdfIn PDF document text
    • http://www.miamiairportlimo.net/wp-content/plugins/formcraft/file-upload/server/content/files/16139641d47b36---jaxokomudonasamobima.pdfIn PDF document text
    • https://profesa.net/userFilesfile/97372453044.pdfIn PDF document text
    • http://epwuae.com/userfiles/file/valelulepafemi.pdfIn PDF document text
    • https://manorhair.com/uploads/files/202109090151365317.pdfIn PDF document text
    • https://cncostruzioni.com/userfiles/file/pelasomi.pdfIn PDF document text
    • http://vipnovini.bg/root/f/uploads/files/82439601638.pdfIn PDF document text
    • https://proartgaleria.hu/files/files/forewubiputaxuveguxisari.pdfIn PDF document text
    • http://zensushialiso.com/uploads/files/kisopatazivawatin.pdfIn PDF document text
    • http://ngocvietbungalow.com/upload/files/zidalijosojagaguvuzolo.pdfIn PDF document text
    • http://minhtoangalaxyhotel.vn/app/webroot/files/ckfinder/files/boluvu.pdfIn PDF document text
    • http://veterinarioassociatopacinidallatorre.eu/userfiles/files/65271745999.pdfIn PDF document text
    • http://artstudiodesign.it/userfiles/files/53219217302.pdfIn PDF document text
    • http://atlantichomeportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/16132fab0137d9---65686918537.pdfIn PDF document text
    • http://www.bufolari.com/public/immagini/file/tevimuwekizere.pdfIn PDF document text
    • http://mothertheresapublicschool.com/userfiles/file/ruxuvotebelenazawupemamu.pdfIn PDF document text
    • http://teusz.pl/UserFiles/file/takuzekakukaduno.pdfIn PDF document text
    • http://amghanoi.com/images/ckeditor/files/sumikeje.pdfIn PDF document text
    • http://equipociclistaugeraga.com/ciclistas/userfiles/file/51971298738.pdfIn PDF document text
    • http://lovesushiscv.com/uploads/files/45254423743.pdfIn PDF document text
    • https://soechi.id/userfiles/file/fekamanefagisibuwit.pdfIn PDF document text
    • http://taxiluzern.ch/khurasan/userfiles/files/radog.pdfIn PDF document text
    • http://lafenicealcamo.it/userfiles/files/vemilekexiwerubizoji.pdfIn PDF document text
    • 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_off0000d7b4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD7B4 17452 bytes
SHA-256: c42a1a4b92e7db6fd89c18745213254a9e7d80dc8f0fb2cb63d709b9dcfd17be
font_01_sfnt_off0001057e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1057E 10864 bytes
SHA-256: 6ca93608ade5ab45d76b28e64281a6d0a29a399edaa275df78b413e30dce1cb2
font_02_sfnt_off00011e58.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E58 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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