Malicious PDF — malware analysis report

Static analysis result for SHA-256 a13c2fd81ae63a37…

MALICIOUS

PDF

86.5 KB Created: 2021-09-19 16:17:08 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: b8b1223417b00272a536ed15c5e96676 SHA-1: 2b6c5b01b5377d69f5e259b28925886887c190fc SHA-256: a13c2fd81ae63a37fb00e63756e8c239c7d4e8af20b106fd7eeafbfec31702c8
164 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs pointing to compromised websites and disposable hosting, indicating a link farm designed to redirect users. Heuristics like 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' and 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggest a malicious intent to host or link to malicious content. The ML classifier and ClamAV detection further confirm its malicious nature, likely as a phishing or malware distribution vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9835

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 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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+phone+wallpaper+download PDF link annotation
    • https://qeyeoptical.com/ckeditor/ckfinder/userfiles/files/56374847006.pdfIn PDF document text
    • https://kozlovka.mebel18.com/uploads/files/36174313166.pdfIn PDF document text
    • http://xn--80aer5aza.xn---42-5cdakyymnnb9ake1az.xn--p1ai/ckfinder/userfiles/files/vikomilezo.pdfIn PDF document text
    • http://kingspec.su/wp-content/plugins/super-forms/uploads/php/files/bejnn27qor52vv7q7mg9k5p90n/fokekutun.pdfIn PDF document text
    • http://tobn56.com/UpFiles/file/madurigaz.pdfIn PDF document text
    • http://www.azurwelcomeservices.com/userfiles/file/89287236680.pdfIn PDF document text
    • http://tentauto23.ru/ckfinder/userfiles/files/58780762463.pdfIn PDF document text
    • http://elpijisystem.com/file/90365695015.pdfIn PDF document text
    • https://gertiesbloomers.com/kousumi/nulook/upload/fckimages/file/disurunurenejumakegotozud.pdfIn PDF document text
    • https://www.dazzlingdecor.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613c64ae741a9---19218877008.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613592a980dc0---diwol.pdfIn PDF document text
    • http://diennuocdanang.com/uploads/image/files/83596920484.pdfIn PDF document text
    • http://daearesort.com/FileData/ckfinder/files/20210902_A2D0C099B93E9BFD.pdfIn PDF document text
    • http://www.coverseg.com/uploads/ckfinder/files/vipesidubemunebokafapim.pdfIn PDF document text
    • http://bluebiz.kr/userData/board/file/62920687750.pdfIn PDF document text
    • https://deycaterers.com/ckfinder/userfiles/files/49628973084.pdfIn PDF document text
    • http://bangladeshceramicsociety.com/uploads/editor/files/beneleronox.pdfIn PDF document text
    • https://xn----8sbcehyodmtf1czh.xn--p1ai/userfiles/file/powulumipukojalume.pdfIn PDF document text
    • http://www.anieliasfx.com/uploads/textareas/file/31624155249.pdfIn PDF document text
    • https://rumusjitu.com/contents/files/10724183683.pdfIn PDF document text
    • http://xboxheerlen.nl/userfiles/file/mijiramigobizivam.pdfIn PDF document text
    • http://contelex.it/userfiles/files/1601452217.pdfIn PDF document text
    • http://xn--80aikni6a0b.xn--p1ai/images/file/sokejopofof.pdfIn PDF document text
    • https://rowsontw.com/shopadmin/upload/files/tubefasivukuboronaku.pdfIn PDF document text
    • http://mingmitrcoffee.com/user_img/files/zeriruwosib.pdfIn PDF document text
    • https://mmrh.myagenda.cz/pictures/editor/files/fafenovofijusiruwetefodi.pdfIn PDF document text
    • http://p-itos.net/admin/userfile/image/file/sidibimegi.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_off0000ee96.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEE96 10292 bytes
SHA-256: a44015c7141621b0273b390745dabb78f2f2c7e9372364d1bd83d110cafb818d
font_01_sfnt_off000105a7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x105A7 18292 bytes
SHA-256: df8377beffd4022063e8302a625fc323a5f93822a059b0447a551ac17d896d31
font_02_sfnt_off0001344f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1344F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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