Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1b87cc7af8fe1f4…

MALICIOUS

PDF

87.1 KB Created: 2021-09-07 13:56:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 18efcedf6b0802ead599ed4f0575073d SHA-1: 41e37d284de50ffe1f337f86bf9cc4cd7ce11fe4 SHA-256: a1b87cc7af8fe1f4f32cf9eb885a067fb15b16b6701e95e5e26896d4d23e4810
172 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF containing embedded JavaScript, which is often used to download and execute further malicious payloads. The PDF also contains numerous links pointing to compromised WordPress sites, suggesting a phishing or malware distribution attempt. The heuristic 'SE_INVOICE_LURE' further indicates a social engineering tactic to trick the user into interacting with the malicious content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9835

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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.
  • Fake invoice / payment lure low SE_INVOICE_LURE
    Document contains invoice or payment language paired with an action verb — useful context when combined with link, macro, or attachment indicators
  • 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://encouragingmath.com/wp-content/plugins/super-forms/uploads/php/files/ab2723a29aca48ea7cd00593b848d9bc/63878041091.pdf In PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/160bb02884a32a---15713165544.pdfIn PDF document text
    • https://www.superioreagle.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092cbf9c1d39---bapifi.pdfIn PDF document text
    • https://www.darrellstuckey.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079c9d538d4d---ribifujejekudufomozalakod.pdfIn PDF document text
    • http://www.adanakursmerkezi.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b1a31d760f---mowipozujazaputemexexize.pdfIn PDF document text
    • https://mission4recruitment.com/wp-content/plugins/formcraft/file-upload/server/content/files/16092fce97f6fc---bevexem.pdfIn PDF document text
    • http://agnieszkapawlik.com/userfiles/file/jodufogo.pdfIn PDF document text
    • http://www.thelawchamber.com/wp-content/plugins/formcraft/file-upload/server/content/files/160956b0bad9d7---xojenimajovikix.pdfIn PDF document text
    • https://glass-haus.ru/wp-content/plugins/super-forms/uploads/php/files/1d6474be9b62096762678f6d92589bcb/45959405833.pdfIn PDF document text
    • http://alphasigmaoverseas.com/userfiles/file/95074010874.pdfIn PDF document text
    • https://samsungklimamodelleri.com/upload/ckfinder/files/52986325589.pdfIn PDF document text
    • http://smeeing.com/userfiles/files/37513086752.pdfIn PDF document text
    • https://planet-for-events.de/userfiles/file/52464882769.pdfIn PDF document text
    • https://www.lesson-online.org/wp-content/plugins/super-forms/uploads/php/files/jje1e8e9m3p16qavh92nr1r9t5/karabininosixuret.pdfIn PDF document text
    • http://escolacaritas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609a534ac7d4e---15059070480.pdfIn PDF document text
    • https://i-chat.tw/js/ckfinder/userfiles/files/16159548297.pdfIn PDF document text
    • https://www.acptechnologies.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a94772d5b86---38302738174.pdfIn PDF document text
    • http://fitviewer.biz/files/file/govojagilew.pdfIn PDF document text
    • http://inoxbienhoa.com/upload/files/kadewulokubaj.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/8t1frrgia3ajvpvohode62vk07/47538175972.pdfIn PDF document text
    • https://sentinels.ro/userfiles/file/vegibekagenimilafetum.pdfIn PDF document text
    • http://www.realisthotel.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5f62545de5---4805538061.pdfIn PDF document text
    • http://gld-lining.com/user_img/files/23051599468.pdfIn PDF document text
    • http://xn--80aaa1acmiejxr6d7fg.xn--p1ai/data/files/78194257107.pdfIn PDF document text
    • http://gzperson.com/uploadfile/files/64258509204.pdfIn PDF document text
    • https://talleresimad.com/images/subidas/files/sokaxowegituwaw.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BkSY9tpko7c/uplcv?utm_term=virtual+assistant+client+intake+form+pdfPDF 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_off0000ede2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEDE2 10940 bytes
SHA-256: 049678e4482ccee1083a48b2020192b626843e28a0acbae63b6245cae3282aa3
font_01_sfnt_off00010743.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10743 18508 bytes
SHA-256: ffec5e3d1e88b8d438be9bd83106829e57297b8c6ddd5a004027bc0157199868
font_02_sfnt_off000136a2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x136A2 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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