Malicious PDF — malware analysis report

Static analysis result for SHA-256 cd4bd21ffb0a6508…

MALICIOUS

PDF

67.9 KB Created: 2021-10-01 11:53:40 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: b31c359c929dbc5ce253aff904a0b71b SHA-1: 56e3870fa0989a6f859b3edd0660214cbdc7386c SHA-256: cd4bd21ffb0a6508c332e93d9b3f962030a2f7d03dc71380e5df12ade384e758
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics, including a high-confidence ML classifier and ClamAV detection as a phishing/trojan. It contains a large number of embedded URLs pointing to various domains, indicating a link farm designed to redirect users to potentially malicious content. The presence of external URIs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://laborke.ru/uplcv?utm_term=s21+ultra+best+apps PDF link annotation
    • http://cosmosimpex.com/app/webroot/ckfinder/userfiles/files/56530338624.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/16140e66b2de1e---dubizenolumo.pdfIn PDF document text
    • http://xdata.pl/app/webroot/img/ckf/files/gozavuponofaxudaxesula.pdfIn PDF document text
    • http://sxsasa.org/images_fck/file/1631949707.pdfIn PDF document text
    • https://yingzhaoliuart.com/upload/file/zuvevim.pdfIn PDF document text
    • http://badaranquehablar.com/userfiles/files/betixuxib.pdfIn PDF document text
    • https://lacgl.org/upload/editor/file/riwepomegegapanasubizofa.pdfIn PDF document text
    • http://limeitec.com/upfiles/editor/files/gegufujegegevovavodimiva.pdfIn PDF document text
    • http://studiotecnicodama.it/userfiles/files/56579510575.pdfIn PDF document text
    • https://lakeshoresmilesdentistry.com/wp-content/plugins/super-forms/uploads/php/files/9n8ff7l71gqkd0blnkqvjbttp5/4155472902.pdfIn PDF document text
    • http://actionelectric.pt/www/wp-content/plugins/formcraft/file-upload/server/content/files/161457793864b4---savajogekosawipezezubewag.pdfIn PDF document text
    • http://daegyung.kr/userfiles/file/20210914114315.pdfIn PDF document text
    • https://408of53crownstreet.com/assets/media/files/19334002112.pdfIn PDF document text
    • http://strap.sk/uploads/file/11655672941.pdfIn PDF document text
    • https://nawaasha.org/userfiles/file/gupubugefisinef.pdfIn PDF document text
    • https://essuances.com/ckfinder/userfiles/files/82957777684.pdfIn PDF document text
    • http://gzwep.com/img/file/202199235019.pdfIn PDF document text
    • https://szalkasszorutacskok.hu/app/webroot/files/content/files/tarok.pdfIn PDF document text
    • http://harnettcountyhba.com/userfiles/file/rotomumuronoporuxu.pdfIn PDF document text
    • http://cjmfgxfollow.morefriendship.com/upload/files/2425800700.pdfIn PDF document text
    • http://vaonhaphatphap.com/images/uploads/files/26544642792.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_off0000ac63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAC63 15152 bytes
SHA-256: 848b5bb50ae68930ac30f6b31058f34bf3589429b1a4f61f32e2aad0b106c586
font_01_sfnt_off0000d2dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD2DD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0000eaf4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEAF4 10416 bytes
SHA-256: 9335e1a9ec02a1df168ee7114715ff22927540c414ec4e9b8f23d5f652435785