Malicious PDF — malware analysis report

Static analysis result for SHA-256 c31adbd2b7ac5f33…

MALICIOUS

PDF

77.6 KB Created: 2021-09-20 12:17:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 8c6cc438d4b31df9e1ba6e09723a63e7 SHA-1: 5650ee855272604319751343783bf493a0e82583 SHA-256: c31adbd2b7ac5f331e87dde456d55470d604e3a05554a945058757d5eeda9089
156 Risk Score

Malware Insights

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

This PDF was flagged by multiple heuristics and a machine learning classifier as malicious, with ClamAV identifying it as a phishing trojan. The file contains numerous external links, many pointing to compromised CMS upload directories or disposable hosting, suggesting a link farm designed to redirect users to malicious sites. The primary attack pattern involves exploiting the PDF format to deliver users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

Heuristics 6

  • 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.
  • 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://medvor.ru/uplcv?utm_term=android+no+audio PDF link annotation
    • http://www.hkwebdesign.com.hk/wp-content/plugins/formcraft/file-upload/server/content/files/161446caee2c63---mimota.pdfIn PDF document text
    • http://rootbeadmill.com/upload_fck/file/2021-9-12/20210912114442523431.pdfIn PDF document text
    • https://ngaa.org.au/application/third_party/ckfinder/userfiles/files/68216906363.pdfIn PDF document text
    • http://joomlacode.org/fckeditor/editor/filemanager/img.php?file=file/33971128913.pdfIn PDF document text
    • https://congthuonghotel.vn/app/webroot/files/images/pages/files/porudobivupeg.pdfIn PDF document text
    • https://www.andeanskyline.com/wp-content/plugins/formcraft/file-upload/server/content/files/16141a6e63d426---56819524369.pdfIn PDF document text
    • https://absoluteanytime.com/media_file/files/files/69151989506.pdfIn PDF document text
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/161430fae80560---dapuwibosolotifefi.pdfIn PDF document text
    • https://cvssteelex.com/ckfinder/userfiles/files/lijopekavaxerulino.pdfIn PDF document text
    • https://www.dogandemir.av.tr/paketler/ckfinder/dosyalar/files/wuwufaluzasaratutiki.pdfIn PDF document text
    • https://adtw1.elfjane.com/ckfinder/userfiles/files/62499760622.pdfIn PDF document text
    • https://saraelv.no/wp-content/plugins/formcraft/file-upload/server/content/files/161419af4b2ffe---55058873822.pdfIn PDF document text
    • https://journeywithmypet.com/ckfinder/userfiles/files/8049736277.pdfIn PDF document text
    • http://sun-tes.ru/files/file/73629747687.pdfIn PDF document text
    • http://millionsdiscount.com/mo_images/files/64079751442.pdfIn PDF document text
    • http://iccjsc.vn/images/uploads/files/72230683808.pdfIn PDF document text
    • http://witnesstherealist.com/wp-content/plugins/super-forms/uploads/php/files/ddd96ab553d92ba3b85b38d3cdd5d0c8/xavotugatofatopos.pdfIn PDF document text
    • http://energo-market.ru/sadm_files/23083916060.pdfIn PDF document text
    • https://www.sblending.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161468a3bf107a---23857814990.pdfIn PDF document text
    • https://gentrilieu.vn/userfiles/file/9515040405.pdfIn PDF document text
    • https://cakkue.com/contents/files/gurarevozogalarowofelaxap.pdfIn PDF document text
    • http://teleinwestor.pl/userfiles/file/58272317159.pdfIn PDF document text
    • https://ckmandarin.com/uploads/vitikamunebab.pdfIn PDF document text
    • http://wangguanhardware.com/userfiles/file/veragesijonepurifop.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_off0000cef9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEF9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e70b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE70B 17168 bytes
SHA-256: 5822336beac9c1fd6d2d65eda83d276dc0042eaf2752ce26ec1a9ea4f8bcc17b
font_02_sfnt_off000113b1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113B1 9880 bytes
SHA-256: b4a88808ee501811d39ad7a644cb4f2985d15fb9d31ab2e4233f0931a8830a9c

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