Malicious PDF — malware analysis report

Static analysis result for SHA-256 4151a8234c9bdbf6…

MALICIOUS

PDF

81.8 KB Created: 2021-09-21 23:01:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: bf68e51f91c4b4f6c92b6e8fbdb2fd60 SHA-1: bfba60fe8b07bc9319dd6d8d228cf32c9fe2ccf5 SHA-256: 4151a8234c9bdbf6458def3562bcd70d1edd55c74d9b253ad8f294d248c8ac6e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' suggests the document is designed to host numerous links on disposable domains, and one embedded URI points to 'coretry.ru' with a query parameter suggesting an 'android security update' lure. This indicates the document is likely part of a phishing campaign to redirect users to malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://coretry.ru/uplcv?utm_term=android+security+update+2021 PDF link annotation
    • https://h16hr15k-h19hr37urn.com/contents/files/firenexagebapewez.pdfIn PDF document text
    • http://sellmysayarah.com/userfiles/files/12960535989.pdfIn PDF document text
    • http://newgrids.com/userfiles/file/rodubexotaz.pdfIn PDF document text
    • http://fitnessklub-impuls.pl/uploads/assets/file/jevurewiwaxetovoxegiwatav.pdfIn PDF document text
    • https://stallion-international.com/userfiles/file/tenuzibowixujivijawovaw.pdfIn PDF document text
    • http://baharemadinah.com/wp-content/plugins/formcraft/file-upload/server/content/files/161470f170398e---38102243417.pdfIn PDF document text
    • https://rjpexport.com/files/melojejuwojibubef.pdfIn PDF document text
    • http://dataprint.ie/uploads/file/21224466550.pdfIn PDF document text
    • http://westhollywood.ilovepokebar.com/uploads/files/47048525005.pdfIn PDF document text
    • http://veterinariacomportamentale.it/userfiles/files/niwopulutobifinowubuk.pdfIn PDF document text
    • http://noithatlekhanh.com/Images_upload/files/finojeno.pdfIn PDF document text
    • http://knupress.com/pds/editor/file/59408206420.pdfIn PDF document text
    • http://saxonrt.hu/img/userfiles/files/kojoga.pdfIn PDF document text
    • http://hyunshin.net/userfiles/file/binibizupavaboza.pdfIn PDF document text
    • https://signika.pl/Upload/file/51133432477.pdfIn PDF document text
    • https://sunwayhk.com/louis/STARKGROUP/ckfinder/userfiles/files/werozisexufedatuvorexem.pdfIn PDF document text
    • http://cerrutistudio.eu/userfiles/files/72094669712.pdfIn PDF document text
    • https://serpavenger.com/ckfinder/userfiles/files/38665045554.pdfIn PDF document text
    • http://vps73.juicy-group.com/editor_upload_image/file/58788577317.pdfIn PDF document text
    • http://ecohort.com/userfiles/files/fokurezuxiwezevewupezi.pdfIn PDF document text
    • http://sziszolg.hu/editor_up/89853465935.pdfIn PDF document text
    • http://mqskin.com/luutru/files/jajozekikod.pdfIn PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fd1943e8f8---kunuvowa.pdfIn PDF document text
    • https://likeevent.it/writable/public/userfiles/file/47705989266.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_off0000d920.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD920 10948 bytes
SHA-256: 5bea2bef515a501b654522642a233b82cd14232f8781e7f8617b8e2af2ff53a9
font_01_sfnt_off0000f2cd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF2CD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010adf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10ADF 17988 bytes
SHA-256: 206c6eba21728715a29d223a421df92895bbe8674e5ac31f456b56bd664bbbb8

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