Malicious PDF — malware analysis report

Static analysis result for SHA-256 c91dbf1638a3c738…

MALICIOUS

PDF

81.6 KB Created: 2021-09-17 23:48:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 15c6123b47503e72e2924e2237416114 SHA-1: c8b008e60dc94f6dd5b710663244de2134eb57ad SHA-256: c91dbf1638a3c738601b7584bbc3bdabcd7036b610dac8fda0a3d1c1c5d55e16
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics indicate the PDF acts as a link farm, directing users to multiple external URLs, some hosted on compromised WordPress sites. The presence of numerous links on disposable hosting and the use of UTM parameters suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • 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 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://wastran.ru/uplcv?utm_term=cpu+auslastung+android PDF link annotation
    • http://rescue119.org/userfiles/file/81941275901.pdfIn PDF document text
    • http://geoman.cz/data/file/64194235071.pdfIn PDF document text
    • https://www.grandeprairie.org/wp-content/plugins/formcraft/file-upload/server/content/files/161343b7492ac2---bozanezodar.pdfIn PDF document text
    • http://intertravel.hu/_user/file/94564242627.pdfIn PDF document text
    • http://www.binghan.my/userfiles/file/90039684403.pdfIn PDF document text
    • https://www.die-umzugsfabrik.com/wp-content/plugins/formcraft/file-upload/server/content/files/16142fa30338ed---wujivesilutefovavomun.pdfIn PDF document text
    • https://www.tctnanotech.com/wp-content/plugins/super-forms/uploads/php/files/ba235d310bf34bc537a7bbd123373244/zurofazoko.pdfIn PDF document text
    • http://1day2night.com/UserFiles/file/nopelosixipagasiviguxete.pdfIn PDF document text
    • http://baltyk.recykling-rejs.pl/imgturysta/files/56751858252.pdfIn PDF document text
    • http://ciba.lv/uploaded/file/lovitevuda.pdfIn PDF document text
    • https://weilmclainboiler.ca/fck_upload/file/60920505044.pdfIn PDF document text
    • http://hyosangjo.com/userfiles/file/20210916215252.pdfIn PDF document text
    • https://smoothnomad.com/wp-content/plugins/super-forms/uploads/php/files/3plq8i3qtj7m95kmvfkmsihk36/30290577287.pdfIn PDF document text
    • https://ambient-interier.cz/files/files/mamijitudikaxevefevi.pdfIn PDF document text
    • https://wendi101.com/userfiles/file/difipusosivozelokak.pdfIn PDF document text
    • http://omeofest.eu/userfiles/files/lofisigoxivunakevujanapu.pdfIn PDF document text
    • http://hum-lucknow.org/test/fckeditor/file/26151695346.pdfIn PDF document text
    • https://spencershaulageltd.co.uk/wp-content/plugins/super-forms/uploads/php/files/1fd27be71a8f4ed52164c72dc9b846e5/73783013363.pdfIn PDF document text
    • http://www.gieskestukadoors.nl/ckfinder/files/files/86944844954.pdfIn PDF document text
    • http://objetivovender.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614457cad4244---90544371525.pdfIn PDF document text
    • https://acmfashion.vn/uploads/files/zoleki.pdfIn PDF document text
    • http://akbmodel.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612fef08dcc23---27643805309.pdfIn PDF document text
    • http://fk-fudosan.1nino3.com/app/webroot/img/userfiles/files/mizefujok.pdfIn PDF document text
    • http://irodori.kir.jp/files/file/3646203049.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_off0000d904.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD904 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f116.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF116 18824 bytes
SHA-256: 729736fd5c7cc4394175663bf4852a64cad399720bc01ef6771e3ca8727311d9
font_02_sfnt_off00012094.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12094 10564 bytes
SHA-256: 680f3c677c61fd91f282855ab3e8bec591a0221b76229421cf6935a8ef867b9d

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