Malicious PDF — malware analysis report

Static analysis result for SHA-256 f55a84239d6d7a88…

MALICIOUS

PDF

69.5 KB Created: 2021-09-25 17:04:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 4517e7fb3787ce0b1bd3230586096e8f SHA-1: 767d5ec00f28c463e98e3b72ccf129a09eb2d609 SHA-256: f55a84239d6d7a8870110ff8d087cd9e3ddcccea214e4e4bddece53280c8e071
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file contains numerous links to external websites, many of which appear to be compromised WordPress installations or disposable hosting. The heuristic firings indicate it functions as a link farm, likely to distribute malware or facilitate phishing attacks. The ML classifier and ClamAV detection strongly suggest malicious intent, with the primary attack pattern being the redirection of users to malicious sites via embedded URLs.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://synerhu.ru/uplcv?utm_term=ten+thousand+million+billion+trillion PDF link annotation
    • http://bjerkelunden.org/content/files/userfiles/file///99362019850.pdfIn PDF document text
    • http://vibrosystem.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1613819e61e7da---11822604022.pdfIn PDF document text
    • http://clinicaveterinariacittadivignola.com/userfiles/files/dalemekugereduzavuwofek.pdfIn PDF document text
    • https://yuktiedu.com/wp-content/plugins/super-forms/uploads/php/files/92275a39b0bf8a0865c0b6405f9a8e78/72787480316.pdfIn PDF document text
    • http://cmuniontravel.com/userfiles/file/vaxidenidivinijopo.pdfIn PDF document text
    • http://bitree.net/ckfinder/userfiles/files/52684779736.pdfIn PDF document text
    • https://friendsofmultisport.com/ckfinder/userfiles/files/82392492332.pdfIn PDF document text
    • https://ryokanclub.com/FileData/ckfinder/files/20210912_65675D8B36218BB9.pdfIn PDF document text
    • https://www.pferde-fuer-unsere-kinder.de/wp-content/plugins/formcraft/file-upload/server/content/files/16130683360f04---detuvamemetaled.pdfIn PDF document text
    • http://pusheng168.com/uploadfiles/20210916124215.pdfIn PDF document text
    • http://uat2.hkha.com.hk/ckfinder/userfiles/files/pabowusesokuzilikonub.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/161344702dc7a9---zulub.pdfIn PDF document text
    • https://www.sterlingsez.com/ckfinder/userfiles/files/rogufaxenedejiwupilifadip.pdfIn PDF document text
    • http://dansensvenner.dk/imagesfile///zafuwaximu.pdfIn PDF document text
    • https://cahayamimpi1.com/contents/files/20605907583.pdfIn PDF document text
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130d678e399c---xawazakusas.pdfIn PDF document text
    • https://trinityautorepairs.com/uploads/files/juvejisiwawuxiwitabur.pdfIn PDF document text
    • http://jngf.cn/files/file/1789459434.pdfIn PDF document text
    • https://urbanshapes.in/userfiles/file/62637922520.pdfIn PDF document text
    • http://2015.letnifestiwal.pl/ckfinder/userfiles/files/majolamonawepi.pdfIn PDF document text
    • https://t4g.nasscomfoundation.org/wp-content/plugins/super-forms/uploads/php/files/9nko8820259adfh44htohvph36/78876138428.pdfIn PDF document text
    • http://xmst.com.vn/app/webroot/uploads/files/37711621774.pdfIn PDF document text
    • http://ty-int.com/files/files/57051506874.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_off0000b317.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB317 14532 bytes
SHA-256: d9c1163ccff2ca4b39db57555cc5dd4b4e2d4682d1f7171f0408f2eb156ccca8
font_01_sfnt_off0000d79f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD79F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000efb6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFB6 10716 bytes
SHA-256: 161c58f20941c19865346a17a2d7bf0fb0b4f835082e2bafa79317ae2baa36c4

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