Malicious PDF — malware analysis report

Static analysis result for SHA-256 2bc161138dd70e18…

MALICIOUS

PDF

86.6 KB Created: 2021-08-29 00:05:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 3c3f48943c2e7ed1e9a4e9cbc08aa52b SHA-1: 1118dc212965905321ee732461540312a5f35ca2 SHA-256: 2bc161138dd70e184bddbe17f6f7428b7897aa74161f1aec694907b444d6abae
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics reveal it functions as a link farm, with many URLs pointing to compromised CMS upload directories, suggesting it's used for phishing or distributing further malware. The PDF structure itself is also noted for duplicate object bodies, which can be a technique to evade detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://ksuskalology.com/images/file/pumomesalodo.pdf In PDF document text
    • http://bogelaipigeon.com/upload/file/kubewav.pdfIn PDF document text
    • http://uk-finansist.ru/userfiles/file/radetu.pdfIn PDF document text
    • https://nailseasupportgroup.com/wp-content/plugins/super-forms/uploads/php/files/f1ecbb6553a1ac1450dd6c1ceaebc182/27984530.pdfIn PDF document text
    • https://finestblogger.de/wp-content/plugins/super-forms/uploads/php/files/vvvmtb8h9ggr4ou423drq0dr6s/nutukukodiruzaxigiku.pdfIn PDF document text
    • http://ourhkg.com/UPFILE/userfiles/files/fopazimalidukulisewixobos.pdfIn PDF document text
    • http://kesifveotesi.com/files/kakuvepimesubexekumoli.pdfIn PDF document text
    • http://trimblehighalumni.com/clients/84492/File/ganusizolurebumumo.pdfIn PDF document text
    • http://polesprogettazioni.com/userfiles/files/90042032120.pdfIn PDF document text
    • https://mashura.co/userfiles/files/12191216666.pdfIn PDF document text
    • http://muzycznescyzoryki.pl/userfiles/file/93655352820.pdfIn PDF document text
    • https://mebelihome.ru/upload_picture/mudoxa.pdfIn PDF document text
    • http://phannhan.vn/files/usersfiles/files/zaputupe.pdfIn PDF document text
    • http://kingtonkatsu.com/uploads/files/motevugoxigitif.pdfIn PDF document text
    • http://www.1atlanticfunding.com/wp-content/plugins/formcraft/file-upload/server/content/files/1610f7f28c17c0---32037151709.pdfIn PDF document text
    • http://matrixuniverzum.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16086ce39a8241---selorubemajodawar.pdfIn PDF document text
    • https://morabia.fi/images/file/14426955352.pdfIn PDF document text
    • https://local-atlas.ru/userfiles/files/fuvurosale.pdfIn PDF document text
    • http://zulassungsdienst4you.de/bilder/file/92704117965.pdfIn PDF document text
    • http://kraljicabih.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d558b39afe---13098974053.pdfIn PDF document text
    • http://kraski-chernila.ru/resources/file/32685343925.pdfIn PDF document text
    • http://aftckwt.com/uploads/file/jakafixepe.pdfIn PDF document text
    • https://braintreeclinics.com/app/webroot/img/files/nevugis.pdfIn PDF document text
    • https://sheenabusesandcoaches.com/userfiles/file/10077961581.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/cv9VXjIrmdE/uplcv?utm_term=over+cooked+eggsPDF 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_off0000f22e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF22E 10228 bytes
SHA-256: 75909abaa3a61ba9f756eb7ab0b816120c392926aa931897c612d0ff0334be9e
font_01_sfnt_off00010911.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10911 17092 bytes
SHA-256: 632896ab87632842e9bae2a61ba8bf1d6c6a66794a7281908a7a3e19b6c41b68
font_02_sfnt_off00013529.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13529 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1