Malicious PDF — malware analysis report

Static analysis result for SHA-256 558c78702bc79665…

MALICIOUS

PDF

72.1 KB Created: 2021-09-29 06:14:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: a91d72bab53ef7a429dc99af31010439 SHA-1: bdd1ed732f03053e3c9e8850c77b65750d078348 SHA-256: 558c78702bc7966506662661173ab254f8adbc408e690947e88876b33ba336df
96 Risk Score

Malware Insights

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

The PDF contains a large number of external URIs and links to compromised CMS uploads, indicating it functions as a link farm. The ML classifier strongly flagged this PDF as malicious. The primary attack pattern observed is the use of a link farm to redirect users to potentially malicious or SEO-manipulated content hosted on various domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

Heuristics 5

  • 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://nomylo.ru/uplcv?utm_term=ios+emojis+on+android+no+root PDF link annotation
    • http://ipost.mn/ckfinder/userfiles/files/kiruwobobarepatotupon.pdfIn PDF document text
    • http://vdgairconditioning.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613cd7197fd06---91690384145.pdfIn PDF document text
    • https://funstore.dialog.org/userfiles/file/govozetub.pdfIn PDF document text
    • http://cowmoo.org/ckfinder/userfiles/files/29259049633.pdfIn PDF document text
    • http://akcihlar.cz/userfiles/file/14139573657.pdfIn PDF document text
    • http://bpsstudio.hu/uploads/faguweje.pdfIn PDF document text
    • https://macjiboter.macjahisa.si/files/file/51841060799.pdfIn PDF document text
    • https://www.ferienhof-schneider.de/wp-content/plugins/formcraft/file-upload/server/content/files/161373b5a8d6f3---78162658249.pdfIn PDF document text
    • https://tefen67.com/userfiles/files/88494314385.pdfIn PDF document text
    • https://mepho.hu/ckfinder/userfiles/files/vidobugutexiwumosagu.pdfIn PDF document text
    • http://www.startservis.sk/novy/ckfinder/userfiles/files/88304136340.pdfIn PDF document text
    • https://angkorphotographyguide.com/userfiles/file/zelukolumekunujitosijere.pdfIn PDF document text
    • http://karinameal.com/imgdish/files/67903178610.pdfIn PDF document text
    • http://ingpiazza.eu/userfiles/files/likagabulolog.pdfIn PDF document text
    • http://ratchadatitan.com/UserFiles/File/wilavobokuboxapo.pdfIn PDF document text
    • http://getsolarny.com/userfiles/file/32133209384.pdfIn PDF document text
    • http://nppgursaraijhansi.in/ckfinder/userfiles/files/48905414586.pdfIn PDF document text
    • http://eastwoodfamily.net/userimages/38328566190.pdfIn PDF document text
    • http://famcareconnect.org/wp-content/plugins/formcraft/file-upload/server/content/files/1614b77c200ed7---vozawurobun.pdfIn PDF document text
    • http://alarcon-v.com/editor_upload_image/file/vivaw.pdfIn PDF document text
    • http://kiajihlava.cz/UserFiles/File/feradanumuguxodonekosevo.pdfIn PDF document text
    • https://charterboatdeliverance.com/uploads/files/43636832301.pdfIn PDF document text
    • http://guidesdugrandlarge.fr/images/import/file/nunogutibodefevaxisib.pdfIn PDF document text
    • http://vkp.ru/upload/global/file/16101525276.pdfIn PDF document text
    • http://unternehmensberatung-hegenbarth.com/userfiles/file/guribasatifejetuj.pdfIn PDF document text
    • https://interno-kazan.ru/upload/files/1632529815.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_off0000b570.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB570 17840 bytes
SHA-256: db6fad5f9cc4d85db5cc0778b67ae64f57b869ba013bad1a9aef25f4bde49ae4
font_01_sfnt_off0000e33d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE33D 10444 bytes
SHA-256: d4f7c4f574ea683affd5bae6c7aafa4c858b8bd478f5483296e2091230ffccdc
font_02_sfnt_off0000fadc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFADC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1