Malicious PDF — malware analysis report

Static analysis result for SHA-256 28331ec1771b633e…

MALICIOUS

PDF

76.1 KB Created: 2021-09-11 19:19:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 0e1e9b562de1f544f1c56ddf8e7d9ecd SHA-1: a44ebb5d943973e837a243969a83fd8d6fdfd879 SHA-256: 28331ec1771b633ec9bdbb0b590bee29f6d1821c0d4deb7419a7f1803da8f1df
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to disposable hosting and are structured as link farms, suggesting a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly indicate malicious intent. The presence of external URIs and the link farm heuristic point towards a phishing or download lure, likely intended to deliver a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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://crysiq.ru/uplcv?utm_term=dead+trigger+2+mod+apk+free+download PDF link annotation
    • https://www.rapn.ru/ckfinder/userfiles/files/femogetazagaruwusox.pdfIn PDF document text
    • https://red-adlay.com/upload/files/jinovejag.pdfIn PDF document text
    • https://iphastkala.com/userfiles/file/55949723370.pdfIn PDF document text
    • http://top-rubber.com/admin/fckeditor/editor/filemanager/connectors/upload/file/91978476673.pdfIn PDF document text
    • https://hpx.com.ua/wp-content/plugins/super-forms/uploads/php/files/bd7c9be670c45b89e4ab8edea5e62f17/24708102427.pdfIn PDF document text
    • http://starinviter.com/ckimagefiles/rinizijaguzaxekipapiso.pdfIn PDF document text
    • http://dalnoboy.org/data/filestorage/upload/files/relagoxiba.pdfIn PDF document text
    • http://businessnavigator.in/ckeditor/uploads/files/73887825244.pdfIn PDF document text
    • https://phongkhamtamthan.net/uploadeditor/files/fufutezigu.pdfIn PDF document text
    • http://ajeah-intl.org/fck_image/file/radamupuberesokutovupo.pdfIn PDF document text
    • http://toyotarent.hk/FileData/ckfinder/files/20210909_443BBBE51387508A.pdfIn PDF document text
    • http://opsir.eu/files/file/rodevopalurez.pdfIn PDF document text
    • https://27061010.com/uploads/files/202109090816378512.pdfIn PDF document text
    • http://richmediahouse.com/admin/uploads/file/46839343585.pdfIn PDF document text
    • https://otterdisplay.com/userfiles/file/zazowarijeg.pdfIn PDF document text
    • http://podolsk-kondicionery.ru/upload_picture/file/xasexadajodokexagebelunoz.pdfIn PDF document text
    • https://vico-inmobiliaria.com/ckfinder/userfiles/files/gezalamobowadunilomezub.pdfIn PDF document text
    • http://abwcrainhwy.com/uploads/files/19943377553.pdfIn PDF document text
    • https://apotekatia.ba/fajlovi/68794301899.pdfIn PDF document text
    • https://lnpro.in/ckfinder/userfiles/files/16401873001.pdfIn PDF document text
    • https://shatalarab-llc.net/userfiles/files/20700625469.pdfIn PDF document text
    • https://virtualpulse.eu/UserFiles/file/dadilujip.pdfIn PDF document text
    • http://binhchuachay.info/Images_upload/files/vasiraburazezuparotik.pdfIn PDF document text
    • http://dentherapia.hu/files/file/velawefamewu.pdfIn PDF document text
    • https://www.emmabowman.com/wp-content/plugins/super-forms/uploads/php/files/cdf3e9b35acc378751bc34782fc8b9d0/66466225637.pdfIn PDF document text
    • http://nujhimachal.in/img/uploads/files/sijopalunujawet.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_off0000c40d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC40D 17316 bytes
SHA-256: f7a5bc3017cf3a8e62b9ac85a5e2160b63f17ff867919ded4fadb7521b670446
font_01_sfnt_off0000f0cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0CF 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000108e6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x108E6 10972 bytes
SHA-256: 4b02f0d8d92ad89366eed4dbc32c5ebd48223fb59b5928f72e00b759a396bef1