Malicious PDF — malware analysis report

Static analysis result for SHA-256 a1533e6a31c75ca1…

MALICIOUS

PDF

92.1 KB Created: 2021-06-25 20:11:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 7234f31a338a8366c8b871c0f7573b1f SHA-1: d1fa2aa2091203c5191617b9807546e3f85e0336 SHA-256: a1533e6a31c75ca1fa6c25522990dfc75a779413c271ecb0a8fbcee30bef4533
96 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file contains numerous links pointing to compromised WordPress sites, indicating a link farm or SEO poisoning attempt. The ML classifier strongly flagged this PDF as malicious. While no scripts were explicitly extracted, the structure and URL patterns suggest it's designed to redirect users to potentially harmful content hosted on these compromised domains.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

Heuristics 5

  • 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.
  • 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://synerhu.ru/uplcv?utm_term=depersonalization+and+derealization+symptoms PDF link annotation
    • http://alvasari.com/wp-content/plugins/formcraft/file-upload/server/content/files/16089d2aa726d1---88320645557.pdfIn PDF document text
    • http://erkerlaender.de/wp-content/plugins/formcraft/file-upload/server/content/files/160753685dcf10---xezepuxewabovexeju.pdfIn PDF document text
    • http://osullivanspressurewashing.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b5881272763---82980070741.pdfIn PDF document text
    • http://qboardapp.com/wp-content/plugins/super-forms/uploads/php/files/c9dd996a4b0371f74555c5b61de50708/14681510093.pdfIn PDF document text
    • http://trackeg.com/en/wp-content/plugins/formcraft/file-upload/server/content/files/1607bf5f8021cf---bavudi.pdfIn PDF document text
    • http://rzn-house.ru/upload/file/dizipusibapenoz.pdfIn PDF document text
    • http://mkconline.com/landmark/ckfinder/userfiles/files/40353268671.pdfIn PDF document text
    • https://moma-restaurant.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a1a11b3574e---moxudasowavudilogem.pdfIn PDF document text
    • https://diversified-nj.com/wp-content/plugins/super-forms/uploads/php/files/73ee4998eecbcfa82b1b67194fe0d35f/bamusejalimobomidiwuz.pdfIn PDF document text
    • http://king-ber.com/UploadFiles/file/20210624141904723.pdfIn PDF document text
    • https://berbagiangka.com/contents//files/giwibiguvanegepijosovuxu.pdfIn PDF document text
    • http://lex-ter.ru/admin/ckfinder/userfiles/files/40288423484.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/50b779d1cb6d6dc6311eeb61ff36942e/30761968000.pdfIn PDF document text
    • https://intelean.com/wp-content/plugins/formcraft/file-upload/server/content/files/16074160a80cac---pikiwubisasalokejip.pdfIn PDF document text
    • http://ezibra.pl/upload//file/98531859423.pdfIn PDF document text
    • https://kes-stv.ru/wp-content/plugins/super-forms/uploads/php/files/76e7039c00e6a67e689ef1fda4316993/36663280011.pdfIn PDF document text
    • http://www.theagentpipeline.com/wp-content/plugins/formcraft/file-upload/server/content/files/16099161021b7b---98836400212.pdfIn PDF document text
    • http://ahdongjiu.com/upload_fck/file/2021-4-29/20210429023309270118.pdfIn PDF document text
    • https://kayakbranson.com/wp-content/plugins/formcraft/file-upload/server/content/files/160891e1aa6100---gozifimadesutosepukages.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_off0001072f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1072F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00011f41.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F41 16956 bytes
SHA-256: 2835a444c5369913c30dec064a3c9089dd4450366986c502697f8eb6ef4c3f1d
font_02_sfnt_off00014ad0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14AD0 10728 bytes
SHA-256: c79c664f351bbc719d0c53a201b0fe1dbb7dfa7e5ce34610188ac561c0e8d802