Malicious PDF — malware analysis report

Static analysis result for SHA-256 873ef0ddfa7f9105…

MALICIOUS

PDF

99.5 KB Created: 2021-07-02 12:37:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-15
MD5: 03a43529c743049f6def6ec1eadd74c0 SHA-1: 692e472a4d1b1f9ea9f9b12462cc28611aff68b8 SHA-256: 873ef0ddfa7f9105671ef758c74330ef2c68be73dc180441f517d597ab4afc9c
236 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

This PDF file was detected as malicious by ClamAV and exhibits characteristics of a social engineering attack (ClickFix). It contains numerous links to external resources, many hosted on compromised WordPress sites, suggesting an attempt to host or distribute malicious content. The presence of PDF_RANDOM_URL_LINK and PDF_SEO_DISPOSABLE_LINK_FARM heuristics indicates a pattern of using disposable or compromised hosting for malicious links. The ML classifier also flagged this PDF with high confidence.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9922

Heuristics 8

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • ClickFix social engineering attack high SE_CLICKFIX
    Document instructs the user to press Win+R or paste a command into a terminal — consistent with ClickFix attacks that bypass macro restrictions by tricking users into running malicious commands directly
  • 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 http://www.brennholz-heinlein.de/wp-content/plugins/formcraft/file-upload/server/content/files/160de8c08f10f0---27067819992.pdf In PDF document text
    • https://www.ccps.mx/wp-content/plugins/super-forms/uploads/php/files/9ccf980fbae4c72a0a232837f65b249f/kezakexis.pdfIn PDF document text
    • https://amagi.la/wp-content/plugins/formcraft/file-upload/server/content/files/160a1aa972d900---86803642977.pdfIn PDF document text
    • http://zelene-centrum.cz/webpagebuilder/ckfinder/userfiles/files/xumonaxirilusarutafas.pdfIn PDF document text
    • http://ambulatorioveterinarioscapindandrea.it/userfiles/files/18891056413.pdfIn PDF document text
    • https://inchirierielicopter.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16091e9ffe97e3---xerurilu.pdfIn PDF document text
    • http://omniatel.it/wp-content/plugins/formcraft/file-upload/server/content/files/160971d6c839df---38822267823.pdfIn PDF document text
    • http://amuseonline.com/absite/userfiles/file/viverilowepitutuvemajirig.pdfIn PDF document text
    • https://weinquartier.at/wp-content/plugins/super-forms/uploads/php/files/1656847d06cc04cf8a25367875c9b0e6/wirugexadopinukibor.pdfIn PDF document text
    • http://france-ex.com/21072020789.pdfIn PDF document text
    • https://www.qbuildsoftware.com/wp-content/plugins/super-forms/uploads/php/files/716037e766ffc8a08c1420292b6097df/91640660708.pdfIn PDF document text
    • http://ahdongjiu.com/upload_fck/file/2021-5-5/20210505105050818274.pdfIn PDF document text
    • http://www.viksexteriors.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af973d9fc3b---19372123442.pdfIn PDF document text
    • http://foire-fromages-et-vins.com/wp-content/plugins/formcraft/file-upload/server/content/files/160da0b6bbdd56---komanajiwigaxuwujedo.pdfIn PDF document text
    • https://jakspravnenapsa.cz/userfiles/file/fubifokogobinezuvi.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607fa6240d72e---lejomusunisuf.pdfIn PDF document text
    • https://blindnow.com/userfiles/file/72472848602.pdfIn PDF document text
    • https://regenerativetherapyforpain.com/wp-content/plugins/super-forms/uploads/php/files/8f1bab4e5851edca0ded530cc0475a0f/58656461440.pdfIn PDF document text
    • https://sport-jicin.cz/dokumenty/9144266880.pdfIn PDF document text
    • http://s-moonlight.com/CKEdit/upload/files/pevigum.pdfIn PDF document text
    • https://www.ideaklinikbursa.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075b1e6628cf---maloxigizi.pdfIn PDF document text
    • http://xn----8sbpvg0afdbe.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/s231ktbi6fgfr4ot5dj0tj0rq0/23042968584.pdfIn PDF document text
    • http://whitefamilyreunion2020.org/clients/4/4c/4c64578d40ee165aaf486c9a1ef3309b/File/tuxubutemutokulo.pdfIn PDF document text
    • https://lcd96.ru/wp-content/plugins/super-forms/uploads/php/files/1067cfa974c22e44772497f0576f9b26/zudemusebepusovafe.pdfIn PDF document text
    • https://www.penyembuhanholistikreiki.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ba524a0608b---61272163993.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/cv9VXjIrmdE/uplcv?utm_term=graphics+cards+connect+the+system+board+to+secondary+storagePDF link annotation
    • 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_off000121e0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x121E0 11208 bytes
SHA-256: 7afcd0e9ea6f3045468ca0f11d41fdb302ceff8b8a7218b684347496a9a9d423
font_01_sfnt_off00013b98.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13B98 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off000153aa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x153AA 16964 bytes
SHA-256: ea4e246e8d5c7c87447405d08501d0d610121fec52a55fe7e49837d7fb75437a

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