Malicious PDF — malware analysis report

Static analysis result for SHA-256 831536a8b07196ff…

MALICIOUS

PDF

78.6 KB Created: 2021-09-13 11:16:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 01cdddc3fb26c726a8f10b14cd30e505 SHA-1: 478fe809c76511ab5cfd2b1f1f645868ebedd6ee SHA-256: 831536a8b07196fff441730ab57b746705c3d4bbfa36589ccb1a869ff86dd8e6
164 Risk Score

Malware Insights

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

The sample is a malicious PDF identified by ClamAV and an ML classifier, containing embedded JavaScript. It functions as a link farm, directing users to compromised WordPress sites, likely to facilitate the download of a second-stage payload. The presence of embedded JavaScript and the nature of the URLs suggest an attempt to exploit vulnerabilities or trick users into downloading further malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9844

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 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://nexxstep.nl/userfiles/file/28134220145.pdf In PDF document text
    • http://www.catalogodecineargentino.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135a36add3b7---7811120316.pdfIn PDF document text
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136f3f5d162c---tetajizepajutadejoven.pdfIn PDF document text
    • http://www.myhhsi.com/wp-content/plugins/super-forms/uploads/php/files/03ce29a11a2194782242dd46eb4c5ad8/lodosudaruzakowafis.pdfIn PDF document text
    • https://aawyx.com/sites/default/imageuser/file/20313417064.pdfIn PDF document text
    • http://www.detskaoptika.cz/ckfinder/userfiles/files/lolobofisemenuletolak.pdfIn PDF document text
    • http://eatoceanic.iorderfoods.com/uploads/files/miwexulirido.pdfIn PDF document text
    • https://remoteyourstaff.com/calisma2/files/uploads/fofimofofolituxuladiral.pdfIn PDF document text
    • http://skup-laptopow.com/wp-content/plugins/formcraft/file-upload/server/content/files/161302e0914282---99402306443.pdfIn PDF document text
    • https://floridainvestment.cz/files/file/294523737.pdfIn PDF document text
    • http://labmansour.com/app/webroot/js/ckfinder/userfiles/files/nolobuvinawifid.pdfIn PDF document text
    • http://orvosvalaszto.hu/uploads/files/vetazazo.pdfIn PDF document text
    • http://fitviewer.com/files/file/rexemewurekogemapibex.pdfIn PDF document text
    • http://www.neslihanonur.com/wp-content/plugins/super-forms/uploads/php/files/0a39d34866629dd6edac280c798409ba/resepupirolerenevavatediv.pdfIn PDF document text
    • https://portsidestrategies.com/wp-content/plugins/super-forms/uploads/php/files/9deacfeddbe4f5dba3069040db76cbf5/75779058584.pdfIn PDF document text
    • https://itscebu.com/upload/file/20210905002608.pdfIn PDF document text
    • http://zadonskiy.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16136cec32c36d---82731926956.pdfIn PDF document text
    • https://stormester.no/files/file/37022734151.pdfIn PDF document text
    • https://vinocastillo.hu/editor_up/93681540894.pdfIn PDF document text
    • http://behtarinekhodetbash.com/files/files/nafiziserenow.pdfIn PDF document text
    • http://colorsoftexas.com/ckfinder/userfiles/uploads/tijikibigazanivet.pdfIn PDF document text
    • https://smwebtechnology.com/arishayurveda.com/userfiles/file/xugewozevenetezerig.pdfIn PDF document text
    • http://canadianartistic.com/userfiles/file/4750853477.pdfIn PDF document text
    • http://rosniyom.com/userfiles/files/vimizonasupewiw.pdfIn PDF document text
    • https://eyescare.vn/app/webroot/upload/ckfinder/files/fuzetibegarunafiludobufu.pdfIn PDF document text
    • http://slovbau.sk/test/userfiles/file/lafekimuzusoliwadil.pdfIn PDF document text
    • https://www.leasing.net.in/ckfinder/userfiles/files/jenedovepumalova.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/1613d27f496016---18397826193.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BkSY9tpko7c/uplcv?utm_term=2nd+year+biology+book+pdf+downloadPDF 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_off0000cd20.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCD20 10864 bytes
SHA-256: bb988e687bf1de8f7da4b448feadfabc7174f882597400a8844f7711c0217486
font_01_sfnt_off0000e5f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5F7 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000fe09.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE09 17980 bytes
SHA-256: e89813de35db69ceed7e3354c07604f9fa7240955ff478c9a6c7f754cb68f156

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