Malicious PDF — malware analysis report

Static analysis result for SHA-256 850ac79430ec0149…

MALICIOUS

PDF

79.2 KB Created: 2021-08-15 12:08:34 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 1693d277ed450da5eacd5fc0e2b07871 SHA-1: 787ebe4ae7046ff5ab1e693115f935db2fafb2eb SHA-256: 850ac79430ec0149dac795a24265cc547a31c3c55e294741166a2fa8766a8774
156 Risk Score

Malware Insights

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

This PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. The heuristics reveal it functions as a link farm, with numerous URLs pointing to compromised CMS uploads and disposable hosting, suggesting an attempt to redirect users to malicious content. The presence of multiple PDF_SEO_DISPOSABLE_LINK_FARM and PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM heuristics strongly supports this attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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://www.lavalledesign.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606d58141ca52---91730169294.pdf In PDF document text
    • https://www.ptlittleflower.org/wp-content/plugins/super-forms/uploads/php/files/fq9i6j159sgls77jarad4fah80/31042523742.pdfIn PDF document text
    • http://kazenergy.kz/wp-content/plugins/formcraft/file-upload/server/content/files/160ac11a96d1c3---9514905775.pdfIn PDF document text
    • https://40parables.com/wp-content/plugins/super-forms/uploads/php/files/c653b4cb8c7f30a3203bb7709809898b/waguzera.pdfIn PDF document text
    • http://schubert-hh.de/image/file/49086631734.pdfIn PDF document text
    • http://vilocom.net/webroot/img/files/xapadun.pdfIn PDF document text
    • https://advicezone.org.uk/wp-content/plugins/super-forms/uploads/php/files/ep7qln4ci19jah8p67gc1cs0bm/15968950492.pdfIn PDF document text
    • https://ajitcoatings.com/uploads/nukataj.pdfIn PDF document text
    • http://mesahighclassof63.com/clients/79820/File/12085263969.pdfIn PDF document text
    • https://fokusmedia.com/images/uploads/jikofisor.pdfIn PDF document text
    • http://birzebbugastpetersfc.com/files/file/61488638993.pdfIn PDF document text
    • https://www.nstoplana.rs/ckfinder/userfiles/files/suwutojibilunevetijazis.pdfIn PDF document text
    • http://trendymamy.pl/userfiles/file/96984200738.pdfIn PDF document text
    • https://communeouchamps.fr/userfiles/file/vubazelonupitada.pdfIn PDF document text
    • https://ecoinkworld.com/wp-content/plugins/super-forms/uploads/php/files/f0c08cafe930dd3f57d1d60583e021a6/kolofoxejepijekati.pdfIn PDF document text
    • http://www.loockuniformes.com.br/home/wp-content/plugins/formcraft/file-upload/server/content/files/16080c74237055---kapuju.pdfIn PDF document text
    • http://conwaychristian.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606ca87c35a8c---nekel.pdfIn PDF document text
    • https://laneopx.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c6925fbd7a2---lolilijuribogozowevifis.pdfIn PDF document text
    • https://www.wflorlando.com/wp-content/plugins/super-forms/uploads/php/files/a7c9115fa45bcd49dd3f18041df4b807/35000156122.pdfIn PDF document text
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/160d2b2ab6e25e---63959735102.pdfIn PDF document text
    • https://vieclamkinhdoanh247.com/upload/files/kozagekig.pdfIn PDF document text
    • https://marblo.ph/app/webroot/img/files/lelezotomubifusofidi.pdfIn PDF document text
    • http://wintec-samu.hu/uploads/files/savutaninopifapisale.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=esl+present+simple+and+continuous+exercisesPDF 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_off0000d381.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD381 10860 bytes
SHA-256: 7f0f94fd2878bbff5ff74569645f1a76299e22c204775c5827c111e1d9fc8333
font_01_sfnt_off0000ec8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC8E 15984 bytes
SHA-256: 292caa6adf4be5d2a1e9cb380db8176b67db98b8289ff51d3b794148eb750ec2
font_02_sfnt_off000115de.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x115DE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1