Malicious PDF — malware analysis report

Static analysis result for SHA-256 83850ffb79a56ebf…

MALICIOUS

PDF

82.3 KB Created: 2021-09-18 22:28:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-02
MD5: c12b81234e798fe5be0700c6f0fbd49d SHA-1: 8b221aecfef2c399111c1ad8409fb79279061a26 SHA-256: 83850ffb79a56ebf6cade7065a2d57dd036a3edf78c23bac7f04399076ccd4e8
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript and numerous external URIs, many of which are part of a link farm hosted on compromised or disposable domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or malware distribution by redirecting users through these links. The embedded JavaScript is likely used to facilitate these redirects or exploit vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 https://crysiq.ru/uplcv?utm_term=spider+man+2+apk+free+download PDF link annotation
    • https://alpinismbihor.ro/app/webroot/files/userfiles/files/68037393650.pdfIn PDF document text
    • http://serendipityorlando.com/wp-content/plugins/formcraft/file-upload/server/content/files/161319028dee0b---liponabuluzerop.pdfIn PDF document text
    • http://xn--aknmedcal-wpbe.com/uploads/file/37808680430.pdfIn PDF document text
    • https://blugarden.eu/file/poxosa.pdfIn PDF document text
    • http://kirks-pool.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ec9ca3a2a1---57535584094.pdfIn PDF document text
    • http://bacvietexpress.com/upload/userfiles/files/69595577397.pdfIn PDF document text
    • http://lynxauto.ru/userfiles/file/60476616355.pdfIn PDF document text
    • https://es21sys.com/userfiles/file/tewesesonujalodezipumoket.pdfIn PDF document text
    • http://www.mmd.ntou.edu.tw/ckfinder/userfiles/files/11640614043.pdfIn PDF document text
    • https://101doctor.com/uploads/ckfiles/files/6145e1d0d02f4.pdfIn PDF document text
    • https://cosmopolitanhotel.eu/uploads/wysiwyg/files/jibanakesu.pdfIn PDF document text
    • http://3q1p.com/upload/file/2109151103029531265k5bmigd211v.pdfIn PDF document text
    • http://sentralperdana.com/file/68828222903.pdfIn PDF document text
    • http://www.ekoforte.com/upload/file/73666093117.pdfIn PDF document text
    • https://best-turbos.com/wp-content/plugins/super-forms/uploads/php/files/c4e2cbd00ae0e2731000e785f916b842/paloxagakixazi.pdfIn PDF document text
    • http://avon-bratislava.sk/files/files/gilob.pdfIn PDF document text
    • https://www.sensormaticltd.com/app/templates/js/ckfinder/userfiles/files/wobapoxa.pdfIn PDF document text
    • https://nhahangthanghuong.com/uploads/files/86741159647.pdfIn PDF document text
    • http://tnslib.net/userfiles/files/difebotakolupegemazifir.pdfIn PDF document text
    • http://0-50.ru/userfiles/file/84029645631.pdfIn PDF document text
    • https://hattoco.vn/images/ckeditor/files/mamorobifalusokojuten.pdfIn PDF document text
    • https://guclupin.com/calisma2/files/uploads/sasuvewisalapuf.pdfIn PDF document text
    • http://kunas.lt/app/webroot/uploads/files/xavuzaxitedubatujej.pdfIn PDF document text
    • https://alohasafaris.com/files/gobatosifupaluri.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_off0000dc63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDC63 18016 bytes
SHA-256: 0b3a845b2364fc0d61ef7ae1c7332ee810daef06ccc971582567d333308ecb87
font_01_sfnt_off00010a81.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A81 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00012298.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12298 10764 bytes
SHA-256: d7e2f8e7ab95a13a0b1fdf6aded67fe49c4260178da6c26df950b3578bc5cf8b