Malicious PDF — malware analysis report

Static analysis result for SHA-256 a33943fa7f11ed83…

MALICIOUS

PDF

80.8 KB Created: 2021-09-11 13:07:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: de2017069988c92f06567ec60347b9e8 SHA-1: 9670a79be1929e4a8e182addd9dc5b262802d640 SHA-256: a33943fa7f11ed8386bf571d8a711bd237f0114b0fb5bd24c284ba228547ded8
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with several URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to obscure the final destination. While no scripts were explicitly extracted, the PDF structure and embedded URLs are consistent with phishing or malware delivery tactics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9960

Heuristics 6

  • 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 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://dieterheich.de/images/uploads/file/28183403876.pdf In PDF document text
    • https://choiceenergynetwork.com/wp-content/plugins/super-forms/uploads/php/files/631d1464d04396dc7baa33177005a996/3853262061.pdfIn PDF document text
    • https://motoralbini.it/files/file/xawofabopewemadaf.pdfIn PDF document text
    • http://fusheng-vietnam.vn/admin/webroot/upload/image/files/43654238695.pdfIn PDF document text
    • http://impactpluslearning.com/ckfinder/userfiles/files/favipafolamaxu.pdfIn PDF document text
    • http://predit.ru/admin/ckfinder/userfiles/files/1148514255.pdfIn PDF document text
    • http://heryeryesil.com/resimlerfiles/xenosipizatuvuxigidesom.pdfIn PDF document text
    • http://ptairsupply.com/userfiles/file/35289014873.pdfIn PDF document text
    • http://salukool.ee/upload/userfiles/file/sulimixixurutigizi.pdfIn PDF document text
    • http://wangguanhardware.com/userfiles/file/xixolakapot.pdfIn PDF document text
    • http://mobilenmr.com/files/files/74939574111.pdfIn PDF document text
    • http://imosa.asia/uploads/files/202109051923464711.pdfIn PDF document text
    • http://clinicaveterinariagoitese.it/userfiles/files/38215206449.pdfIn PDF document text
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/noretobepumokaforumekepa.pdfIn PDF document text
    • http://nyitotthaz.hu/userfiles/files/vutupesi.pdfIn PDF document text
    • http://tucholainfo.pl/userfiles/file/periga.pdfIn PDF document text
    • https://www.vibrationmonitoring.asia/wp-content/plugins/formcraft/file-upload/server/content/files/16131f1d17b022---53240384053.pdfIn PDF document text
    • https://hoalavender.net/upload/files/widarexipelurixub.pdfIn PDF document text
    • http://lingvastar.z-i-g-z-a-g.com/userfiles/files/83142877152.pdfIn PDF document text
    • http://stihoplet.by/upload/editor/files/tefud.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/161381d4e79ec5---99044606709.pdfIn PDF document text
    • http://myphamnanyno.com/luutru/files/10241376223.pdfIn PDF document text
    • http://eventclub.pl/userfiles/file/garisaxasitaweropuvus.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/fzgW7-mxBc0/uplcv?utm_term=odtwarzacz+wma+na+androidaPDF 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_off0000d910.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD910 17348 bytes
SHA-256: 23e574c3ea65721bff8af5986541e656daecec7271c1ab70aaaaf4d284a331c7
font_01_sfnt_off000104d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104D3 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00011cea.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11CEA 10356 bytes
SHA-256: 7947d9e7e63fc4385b88750db232042a0063cd81d80ce9fff915ea797b831f3a