Malicious PDF — malware analysis report

Static analysis result for SHA-256 83e4e1fe1c58d5d3…

MALICIOUS

PDF

84.3 KB Created: 2021-09-06 14:47:12 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d4a3f0eb55664ca25d73620a02e41a6a SHA-1: 01c0c2fbf1bad497f923174709a4b8c9099e3dcd SHA-256: 83e4e1fe1c58d5d35e4134f13b407334e28be5b04933d150c0181095954d48f9
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a phishing or trojan threat. It contains numerous external URIs and embedded links that point to various websites, many of which appear to be compromised WordPress installations. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests the document's primary purpose is to act as a link farm, potentially for SEO manipulation or to redirect users to malicious content. No scripts were extracted from this sample, but the presence of numerous links to potentially compromised sites is a strong indicator of malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://cructi.ru/uplcv?utm_term=math+transformation+worksheet+pdf
    • https://agilitynd.com/wp-content/plugins/super-forms/uploads/php/files/0b33865434bcdb50c10caf3483748b1d/72838871608.pdf
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16088ecb25dd0d---sibarar.pdf
    • https://www.accidentinjurylascruces.com/wp-content/plugins/super-forms/uploads/php/files/3p6ph230ps1qvfj0da9fhtg1mu/42706197619.pdf
    • http://elsekmont.eu/userfiles/file/22608253634.pdf
    • http://www.bargiel.com.pl/ckfinder/userfiles/files/lifazenuwovepufusi.pdf
    • http://progfin.pl/userfiles/file/38694282364.pdf
    • http://phuocthuan.vn/images/pic/file/tebewofosodorex.pdf
    • http://ipllaser.in/uploads/bokawetitidosivisikodum.pdf
    • http://sklepjola.pl/userfiles/file/segede.pdf
    • https://nam.it/wp-content/plugins/formcraft/file-upload/server/content/files/1607db37422b3b---tofemawodon.pdf
    • http://bascobrunswick.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160782e0173933---zorebasabojiz.pdf
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/bda892c98dd2b12827d740542a3e98ac/gijevukosa.pdf
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16077f9f7472ec---viworidoparogolofizupux.pdf
    • https://duhocblueocean.vn/ckfinder/userfiles/files/3215256045.pdf
    • https://tractorpulling-emmeloord.nl/upload/file/26716777813.pdf
    • https://www.grecosalesinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d3eaea00fc4---79711823624.pdf
    • https://www.cedicar.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b56f3c9c85e---76041357785.pdf
    • http://murielbellhomes.com/userfiles/files/desedikamo.pdf
    • http://sapaelitehotel.com/webroot/img/files/17088626637.pdf
    • https://bilalyapidekorasyon.com/userfiles/file/jadoseneduderolog.pdf
    • https://cr2tek.com/userfiles/Proj_Name//files/pezipujaranepetetone.pdf
    • https://mayxaydungthienlong.com/uploads/files/files/vurufufavi.pdf
    • https://celebicatering.com/upload/ckfinder/files/zisiwidomavud.pdf
    • https://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1611d596c9d87e---405854997.pdf
    • http://azizolace.cz/images/file/zajenogafivowavaf.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_off0000e419.bin
b06861e6d7a25110af7eb4fb6e5c329fe185e0750f7cce6fbc945ac1022a2b30
pdf-font-stream PDF embedded font (sfnt) at offset 0xE419 17652 bytes
font_01_sfnt_off000111e3.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x111E3 16792 bytes
font_02_sfnt_off000129fa.bin
708dab8dba2f61dc73dab7f3d03ccccf1e6306de3ab20f0fe882023fce6014d1
pdf-font-stream PDF embedded font (sfnt) at offset 0x129FA 10888 bytes