Malicious PDF — malware analysis report

Static analysis result for SHA-256 b9b6a4ae4283f137…

MALICIOUS

PDF

75.2 KB Created: 2021-09-24 05:11:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 804791b021e6d1ed84ee39a7d52c5320 SHA-1: a76a00a2eb6f649213719082b06bce665029e287 SHA-256: b9b6a4ae4283f1376b099c054fd73958f0c660ede8c0e04f577437ee150a263f
156 Risk Score

Malware Insights

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

The file was identified as malicious by a ClamAV detection and an ML classifier, indicating a high likelihood of malicious intent. It contains numerous links to external websites, many of which are hosted on compromised or disposable domains, suggesting a link farm used for phishing or malware distribution. The presence of external URI heuristics and link farm indicators further supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9971

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 http://22vek-omsk.ru/fck_editor_files/files/13986896308.pdf In PDF document text
    • http://bluetact.com/ckfinder/userfiles/files/wewanovamofadapafodasapo.pdfIn PDF document text
    • https://taxfirma.com/userfiles/file/49954115425.pdfIn PDF document text
    • http://ne-moloko.ee/wp-content/plugins/super-forms/uploads/php/files/8e11cb76977fd242239035037254cbd5/bekifen.pdfIn PDF document text
    • https://jmbarrenetxea.soinuenea.eus/files/galeria/files/42232196872.pdfIn PDF document text
    • http://jnnycc.org/userfiles/file/bejesutiv.pdfIn PDF document text
    • https://fokusmedia.com/images/uploads/sibep.pdfIn PDF document text
    • http://latiendasegura.com/contable_prueba/userfiles/file/gumupikaboxopubukuwujaza.pdfIn PDF document text
    • http://rjbmachinery.com/d/files/gimimozagoturugeriz.pdfIn PDF document text
    • http://tnshoppingbag.com/upfiles/file/sazasonosa.pdfIn PDF document text
    • http://aquarium-kochi.com/app/webroot/ckfinder/userfiles/files/98567333462.pdfIn PDF document text
    • http://execdentalclinic.com/uploads/ckfinder/userfiles/files/62694734257.pdfIn PDF document text
    • http://educaholistica.com/resources/img/imagesck/files/11899610899.pdfIn PDF document text
    • http://rydelko.eu/userfiles/file/25373914183.pdfIn PDF document text
    • http://www.maderas-navarro.com/ckfinder/userfiles/files/40125797623.pdfIn PDF document text
    • http://bsp-oblspl.org/ckfinder/userfiles/files/95870486803.pdfIn PDF document text
    • https://mavismanagement.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fa081c2b4e---11159396192.pdfIn PDF document text
    • https://signika.pl/Upload/file/95594400750.pdfIn PDF document text
    • http://www.niceresidence.net/image/upload/File/fufobesolutevozokipesopi.pdfIn PDF document text
    • https://asztromiskolc.hu/ckfinder/userfiles/files/90552756732.pdfIn PDF document text
    • http://www.telsercom.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139e3780179e---nuzeforufajojirubinumo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=apk+free+tips+app+downloadPDF 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_off0000bf1f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBF1F 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000d736.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD736 10648 bytes
SHA-256: a2e0006fd94fbbe9050e76bd358d5045fcd414da77d5c2ce8ad2a19f96e52ffa
font_02_sfnt_off0000efd2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEFD2 18536 bytes
SHA-256: 7a178de70f37cdf243cac8210c7ce6b0af50b5c14558bcc11655d07e77cbb343