Malicious PDF — malware analysis report

Static analysis result for SHA-256 91c0fd84fc569665…

MALICIOUS

PDF

76.1 KB Created: 2021-09-21 00:31:15 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: fd23bda663660635dcd9c38430005e7e SHA-1: b26402e7607a517683f447f4226c1db9e51d1eb3 SHA-256: 91c0fd84fc569665e11a0e4da6ad6280101409bd14d2f25e68e3b66d4f37e380
204 Risk Score

Malware Insights

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

The sample is a PDF document containing embedded JavaScript and a large number of external links. Several heuristics indicate that these links are part of a link farm, with some pointing to compromised WordPress uploads and disposable hosting, suggesting a phishing or malware distribution attempt. The embedded JavaScript likely facilitates the redirection to malicious sites or exploits vulnerabilities.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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 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.
  • 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://wastran.ru/uplcv?utm_term=imo+hacker+app PDF link annotation
    • http://webursitet.org/Files/file/3731621120.pdfIn PDF document text
    • https://www.poolsrus.com.au/application/third_party/ckfinder/userfiles/files/48920002032.pdfIn PDF document text
    • http://circuitvietnamcambodge.com/hinhanh/file/89976889608.pdfIn PDF document text
    • http://travelport.pl/userfiles/file/tijedulizalub.pdfIn PDF document text
    • http://msmzizkov.cz/data/dokumenty/49346441386.pdfIn PDF document text
    • http://www.kidnuri.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133fb54c28e9---melajonu.pdfIn PDF document text
    • http://ventiliatoriai.lt/js/ckfinder/userfiles/files/15831062341.pdfIn PDF document text
    • http://everest-c.ru/ckfinder/userfiles/files/merelekonilorokaw.pdfIn PDF document text
    • http://chagatea.ru/wp-content/plugins/super-forms/uploads/php/files/8b7afc0cba36a34ae49ba53e16fa4354/feketoxowu.pdfIn PDF document text
    • http://ieltsadd.ir/cache/fck_files/file/91937577834.pdfIn PDF document text
    • https://theshamrockpublecco.it/file/wobapimisorikosubexiba.pdfIn PDF document text
    • https://xanbiente.de/userfiles/file/26895944617.pdfIn PDF document text
    • http://cplust.com/upload/serback/files/20210916182755.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613131ab4226b---dupijopugalawovisoxarofes.pdfIn PDF document text
    • http://pcserviszlin.cz/ckfinder/userfiles/files/55987393134.pdfIn PDF document text
    • https://xn--bankkrtya-41a.hu/js/ckfinder/userfiles/files/sevowa.pdfIn PDF document text
    • https://whiteplacard.com/UserFiles/file/rafevopurosasa.pdfIn PDF document text
    • http://angelofthewinds.org/ckfinder/userfiles/files/58984753466.pdfIn PDF document text
    • https://oglethorpeclub.org/~oglethor/UserFiles/file/15144733870.pdfIn PDF document text
    • https://nk-sostanj.si/files/file/pinejalitegoloxagajalade.pdfIn PDF document text
    • http://poetische-malerei.de/web/editor/files/vabisopexipaforadonaxa.pdfIn PDF document text
    • http://remontnoedelo.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16147713198cbd---rozeloduleriwojemufowovi.pdfIn PDF document text
    • http://lambanghieuquangcaogiare.net/vietkiendo/upload/file/86980172208.pdfIn PDF document text
    • https://internationallanguagenavigators.com/media/66187471214.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_off0000c4e7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC4E7 10176 bytes
SHA-256: 0d22bc24bf89cdea2e67422cfa95f9a27c6c81f4ef40e8264742f6b3e687b48c
font_01_sfnt_off0000dbaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDBAA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000f3bc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF3BC 18340 bytes
SHA-256: 7f4943420014a9b5410f899980af1d35c8fa8c0f42581a1933db2734d1fc2fc9

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