Malicious PDF — malware analysis report

Static analysis result for SHA-256 4877cb81540343dd…

MALICIOUS

PDF

78.0 KB Created: 2021-09-18 04:49:05 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: acef7792bb8dcc199cb3b5728ed45a43 SHA-1: 3b0f2173bce2080009490632f3b73510f7866b56 SHA-256: 4877cb81540343dd42847e01b5525c03e18eeedc7b6d45ea5e9b42d6b441dccf
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm. The PDF contains numerous external URIs pointing to various domains, many of which appear to be compromised or disposable hosting, suggesting an attempt to distribute malicious content or phish users. No scripts were extracted, but the structure and URL patterns are consistent with a malicious PDF dropper.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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 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://oniceh.ru/uplcv?utm_term=android+sub+activity PDF link annotation
    • https://karinbentum.nl/uploads/file/seduxonoxixarujawoworozaz.pdfIn PDF document text
    • http://xfswchem.com/upload/files/12632033367.pdfIn PDF document text
    • http://www.kevinbrooks.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1612eeb5a17d42---xeguf.pdfIn PDF document text
    • http://xn----9sbkvfu2aex3d.xn--p1ai/ckfinder/userfiles/files/bowutoget.pdfIn PDF document text
    • http://bafiti.com/sklep/userfiles/file/95386931547.pdfIn PDF document text
    • https://inarsindbari.org/uploads/lifumazax.pdfIn PDF document text
    • https://drahmetbostanci.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e04f5a6f29---puteboruwopaberure.pdfIn PDF document text
    • https://birutelorasin.com/contents/files/kakedexu.pdfIn PDF document text
    • https://oreopay58.com/ckfinder/userfiles/files/zafuduxiwoxokikulob.pdfIn PDF document text
    • https://www.arc-welding.co.uk/wp-content/plugins/super-forms/uploads/php/files/e4vsn87ql2dshg8qippqfnc07e/juxavisatet.pdfIn PDF document text
    • http://gddfboiler.com/uploads/files/binuri.pdfIn PDF document text
    • http://tmacfashion.com/ckfinder/userfiles/files/7238895662.pdfIn PDF document text
    • https://akonis.ch/userfiles/files/16268762276.pdfIn PDF document text
    • https://khabul.mn/mmpa/userfiles/files/7020735467.pdfIn PDF document text
    • http://jongauger.com/userfiles/file/85432825882.pdfIn PDF document text
    • http://vinaktv.com/storage/ckfinder/files/9582756564.pdfIn PDF document text
    • http://thongthien.vn/upload/files/31123773671.pdfIn PDF document text
    • https://hattshopping.com/admin/assets/images/ckfiles/70075876727.pdfIn PDF document text
    • http://isagenixmakessense.com/ckfinder/userfiles/files/tiluken.pdfIn PDF document text
    • https://harmony.im/userfiles/file/5873567290.pdfIn PDF document text
    • https://kheops-so.fr/ckfinder/userfiles/files/50712601940.pdfIn PDF document text
    • https://bawwabatrizq.com/userfiles/file/85254334144.pdfIn PDF document text
    • https://clinicamanila.com/ckfinder/userfiles/files/zerazemagumewon.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_off0000ca4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCA4D 10588 bytes
SHA-256: 57053ce1dc9fbae899dbc7706b34122e1d6e951887cd0a00561ebfb73ffb62d9
font_01_sfnt_off0000e2ab.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2AB 18380 bytes
SHA-256: 2a396aca15fe9f3d3c37f4c3b14ea01cd27f6af1a83bfea0c8b3bee92fd01de6
font_02_sfnt_off00011272.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11272 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1