Malicious PDF — malware analysis report

Static analysis result for SHA-256 16681d4e45a2c6fb…

MALICIOUS

PDF

69.7 KB Created: 2021-09-25 13:12:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 56e769e264e407187b15b16b73925fbe SHA-1: 8f6df9a32e2d1a87795cb46c529016019dfca027 SHA-256: 16681d4e45a2c6fbe5d58121d49e7fc6776ef2998ca83e4852642a39e7256ed0
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, many of which are hosted on disposable domains or compromised CMS upload directories. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates the document functions as a link farm, likely to redirect users to malicious sites or for SEO manipulation. The ML classifier strongly flagged this PDF as malicious, supporting the assessment of a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 6

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://crewmak.ru/uplcv?utm_term=beginning+c%23+7+programming+with+visual+studio+2017+pdf PDF link annotation
    • http://futimisdev.com/userfiles/file/54271697989.pdfIn PDF document text
    • http://mjacz.cz/soubory/files/midurigeg.pdfIn PDF document text
    • https://masukpt1.com/contents/files/vipumiki.pdfIn PDF document text
    • https://www.renfrewareahealthvillage.ca/ckfinder/userfiles/files/82024481656.pdfIn PDF document text
    • http://iburgisidimarsala.eu/userfiles/files/26508277567.pdfIn PDF document text
    • https://goldengrowers.com/wp-content/plugins/super-forms/uploads/php/files/3cf9b1d4e1b14444d9b076a81827c6f2/vifogivomotosorilejusad.pdfIn PDF document text
    • https://kodcomputers.ro/2664/uploads/mavagami.pdfIn PDF document text
    • http://foxadv.net/file/48094487115.pdfIn PDF document text
    • http://lokalizacja-gps.pl/userfiles/file/gofomizobolaridata.pdfIn PDF document text
    • http://cioccolatogallucci.it/userfiles/file/62203507845.pdfIn PDF document text
    • https://radiosmile.hu/upload/file/pijuso.pdfIn PDF document text
    • https://jogamiskolc.hu/ckfinder/userfiles/files/mibukotujixozifowil.pdfIn PDF document text
    • http://cargo3030.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1613b1c08e8762---wizadotozafisanoweg.pdfIn PDF document text
    • http://ap116.ru/userfiles/file/60079698457.pdfIn PDF document text
    • http://peknanevesta.sk/media/file/xuvowuwumuzokeke.pdfIn PDF document text
    • http://cmtoolsrental.com/user_img/files/tozamu.pdfIn PDF document text
    • http://bacvietexpress.com/upload/userfiles/files/jilewesoboj.pdfIn PDF document text
    • https://codefon.hu/js/ckfinder/userfiles/files/pesok.pdfIn PDF document text
    • https://abhimaninteriors.com/ckfinder/userfiles/files/kipalumewewudafezitel.pdfIn PDF document text
    • http://mecateengenharia.com.br/ckfinder/userfiles/files/vurevodabatabegonarap.pdfIn PDF document text
    • https://clickbox.ro/images/file/bozujenedexut.pdfIn PDF document text
    • http://ephtour.com/FileData/ckfinder/files/20210909_7726173CE71A7798.pdfIn PDF document text
    • http://intechsol.kz/wp-content/plugins/formcraft/file-upload/server/content/files/16149ace5054d4---nuditowoxigiwakat.pdfIn PDF document text
    • http://vetcasatenovo.it/userfiles/files/23913664316.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_off0000b1e9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB1E9 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c9fb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC9FB 15940 bytes
SHA-256: 873798e82d7ba401a2af11db26fc11a7975c8a9b4e61e317d769a9bfd2014633
font_02_sfnt_off0000f27c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF27C 9764 bytes
SHA-256: acbe612faf2121009665e61d9fd1197c1f5bd08803c0c7035fa907f572310fb5