Malicious PDF — malware analysis report

Static analysis result for SHA-256 cf5453e17fd55df4…

MALICIOUS

PDF

74.3 KB Created: 2021-09-18 08:11:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-21
MD5: ca13c607bac0b20da7d873e5c2e00f98 SHA-1: add3451d6f741fdc4e808d87a8b69b68509d133f SHA-256: cf5453e17fd55df49ef2ed2a175374ccd9a21d3d8eafc4c84c9eb207754a69e2
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is identified as malicious by ClamAV and an ML classifier, with multiple heuristics indicating it's a link farm on disposable hosting. The embedded URLs and the PDF structure suggest an attempt to redirect users to malicious sites, likely for phishing or malware distribution. No scripts were extracted, but the PDF structure itself is used to host numerous links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9947

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://nomylo.ru/uplcv?utm_term=arm+arm64+x86+selection+guide+for+android PDF link annotation
    • https://petpetmates.com/files/editor/file/budusulemo.pdfIn PDF document text
    • http://kubabus.cz/novy-web/upload/file/powadasowikixonub.pdfIn PDF document text
    • http://elektro-galerie-hamburg.de/userfiles/file/pufur.pdfIn PDF document text
    • https://dorfadvertising.com/ckfinder/userfiles/files/29947391175.pdfIn PDF document text
    • https://texasbordervolunteers.org/userfiles/file/14139756278.pdfIn PDF document text
    • http://kingtonkatsu.com/uploads/files/27751216907.pdfIn PDF document text
    • http://crocepadrekolbe.it/userfiles/files/55065639172.pdfIn PDF document text
    • https://www.hauptsache.cc/wp-content/plugins/formcraft/file-upload/server/content/files/16133015502715---82966077826.pdfIn PDF document text
    • https://suthuytinh.com/app/webroot/uploads/files/1835154828.pdfIn PDF document text
    • https://baptistfriends.org/media/84580068467.pdfIn PDF document text
    • https://cplastik.eu/data/cms/file/68074281414.pdfIn PDF document text
    • http://xn--80aafbjcazdrhzgiddbbcsg4l.xn--p1ai/pict/file/24762797651.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/23981214057.pdfIn PDF document text
    • https://art4you.sk/editor_uploads/system/files/905678881.pdfIn PDF document text
    • https://cafemocion.com/userfiles/file/jotaku.pdfIn PDF document text
    • http://indyskischool.com/ckfinder/userfiles/files/nojasisisaziw.pdfIn PDF document text
    • http://tythb.cn/uploadfile/files/10634138519.pdfIn PDF document text
    • http://toitureetfacade.fr/data/Files/besetoxozexavamimeniwaram.pdfIn PDF document text
    • http://veszpremlizards.hu/_user/file/jomikisu.pdfIn PDF document text
    • http://busto-wl.gattinonimondodivacanze.it/themes/userfiles/files/safedewazuvigozizowarig.pdfIn PDF document text
    • http://teranor.com/ckfinder/userfiles/files/zobunazepemakigekalokagi.pdfIn PDF document text
    • http://pcwenhua.com/uploadimg/file/16318098291732229615.pdfIn PDF document text
    • http://actionelectric.pt/www/wp-content/plugins/formcraft/file-upload/server/content/files/161455eacd249f---fibonobaxip.pdfIn PDF document text
    • http://darangyi.com/userData/board/file/sukexemojolamugomi.pdfIn PDF document text
    • http://wildpflanzen-planung.de/file/buximibifa.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_off0000bec4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBEC4 16344 bytes
SHA-256: ad2d9dcd4894e675bcd05c470c0e8945a00c732c49a42cb86d444f45ba468849
font_01_sfnt_off0000e8be.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8BE 11456 bytes
SHA-256: fce6c1b2b3aed302db3639f4d21b9cf5aa1f8eb52b2fe2fe263a5c1efd4731a8
font_02_sfnt_off000103ba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x103BA 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1