Malicious PDF — malware analysis report

Static analysis result for SHA-256 84f4e8f6fdbd5d9a…

MALICIOUS

PDF

91.5 KB Created: 2021-09-11 17:49:54 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 4645b1c66377737c59563fe796315c17 SHA-1: 3be8084e948946213211cd4a70fe6a49284a5bb2 SHA-256: 84f4e8f6fdbd5d9a7367ba0730384ad547f40c933abadec1789c78a8450a7cb4
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains multiple heuristic firings indicating it is a link farm designed to host numerous external URIs, with a high-confidence ML classifier and ClamAV detection confirming its malicious nature. The presence of algorithmically generated URLs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic suggest a phishing or malware distribution campaign. No scripts were extracted, but the structure points to the file's primary function being to redirect users to malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9937

Heuristics 6

  • 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.
  • 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://celeb.huh.hu/UserFiles/File/33286734297.pdf
    • https://seo-methodes.com/userfiles/file/nosudojavulumari.pdf
    • http://geredekombiservisi.com/userfiles/file/bixovowozimevek.pdf
    • http://fqcycpa.com/jingkelun/userfiles/files/20210908020236.pdf
    • http://atol-res.pl/uploads/file/15151591845.pdf
    • http://studiozoppini.com/userfiles/files/nibuvesemulujuzekosulu.pdf
    • https://minhgianggroup.vn/upload/files/dokafadaforozediduge.pdf
    • http://www.reeder.ee/files/filemanager/xugebafejogemudep.pdf
    • https://francoisdaulte.com/ckfinder/userfiles/files/marodofo.pdf
    • http://www.mtpartnersfl.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613b8e42d50c3---3284177026.pdf
    • http://maszyny.pl/userfiles/file/59258884250.pdf
    • https://equantumconsulting.com/files/files/miguminika.pdf
    • http://lucidarepavimentimarmogenovaealessandria.it/userfiles/files/36246975637.pdf
    • https://asharfilalkulfi.com/ckfinder/userfiles/files/67457104816.pdf
    • http://businessdevelopmentcenter.pl/uploads/userfiles/files/4443860199.pdf
    • http://sangtaoad.com/uploads/userfiles/file/difugugepis.pdf
    • http://federicozucchettiarchitetto.eu/userfiles/files/75567729375.pdf
    • http://www.catalogodecineargentino.com/wp-content/plugins/formcraft/file-upload/server/content/files/16138c7b04115c---61206911092.pdf
    • http://natur-pet.cz/webpagebuilder/ckfinder/userfiles/files/xeguwew.pdf
    • https://gizaviation.com/uploads/files/ziripurewubogararojekomar.pdf
    • http://iranjobex.com/cache/fck_files/file/bidimujatiwuxadakapawuw.pdf
    • https://www.abrasco.org.br/ckfinder/userfiles/files/zexugogiwulelamowinawaw.pdf
    • http://bebsulmare.com/userfiles/files/48557857097.pdf
    • https://tumujerrusa.com/userfiles/mojerixoxaxugev.pdf
    • https://aptitudeclass.com/ckfinder/userfiles/files/13743986066.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=c2+vocabulary+list+ielts+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000fc90.bin
431d7cdca0ee3038317aeb6972623606e7b82d48185f75fddc7436f930216951
pdf-font-stream PDF embedded font (sfnt) at offset 0xFC90 11080 bytes
font_01_sfnt_off00011674.bin
56cd90c811210fd06145dc5edbb8b9a23e129ba46771b227969e6bc895b4acc0
pdf-font-stream PDF embedded font (sfnt) at offset 0x11674 19108 bytes
font_02_sfnt_off00014839.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x14839 16792 bytes