Malicious PDF — malware analysis report

Static analysis result for SHA-256 8866fc8383fffd4d…

MALICIOUS

PDF

77.0 KB Created: 2021-06-23 08:43:02 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-08-20
MD5: 43db6ced878f8d9f967dc1f97d65ecee SHA-1: 85bd17a422a1cc5fa7f1599a4842c0c7ed06504f SHA-256: 8866fc8383fffd4d46df434688382b572ee692e9fd0e5675f5eba47c95a33546
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

This PDF file was detected as malicious by ClamAV and a machine learning classifier. It contains multiple links pointing to compromised WordPress sites and disposable hosting, suggesting a phishing or malware distribution campaign. Notably, the document body contains an explicit instruction to 'Disable firewall pfsense', indicating an attempt to impair defenses. The presence of external URIs and a link farm further supports a malicious intent, likely to lead the user to a malicious site or download a secondary payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Security software disable instruction high SE_SECURITY_BYPASS
    Document instructs the user to disable antivirus or security software — unusual for ordinary documents and high-risk in an unsolicited file
  • 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://laborke.ru/uplcv?utm_term=disable+firewall+pfsense PDF link annotation
    • https://www.adcgrain.com/wp-content/plugins/super-forms/uploads/php/files/a28dca4a431834e8bbeade4859cb8098/51475537494.pdfIn PDF document text
    • http://socialbomjesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/160781eb141dc3---67926808963.pdfIn PDF document text
    • https://www.acptechnologies.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608085ca7ee82---jafudesavofeverazubawarim.pdfIn PDF document text
    • http://czapla-dachy.pl/public/images/fck/file/meramuk.pdfIn PDF document text
    • https://schilderlesvakantie.nl/ckfinder/userfiles/files/xeviwadoxevubavazevon.pdfIn PDF document text
    • https://systematix.pl/userfiles/file/damenuxilaruk.pdfIn PDF document text
    • https://thewentworthco.com/wp-content/plugins/super-forms/uploads/php/files/qalmbvtks2k5m4ere8q5jrba6s/16138921488.pdfIn PDF document text
    • http://fixmyhelicopter.com/project-new/christianbook/upload_images/file/joxawis.pdfIn PDF document text
    • https://blsautomation.com/ckfinder/userfiles/files/fedegejejojomi.pdfIn PDF document text
    • https://carthink.org/wp-content/plugins/formcraft/file-upload/server/content/files/1609baed68bfb8---49844088898.pdfIn PDF document text
    • https://bluza-shop.ru/content/File/laserawejanofobixug.pdfIn PDF document text
    • http://sterenstein.ru/userfiles/file/kegimonox.pdfIn PDF document text
    • http://bridgesonthepark.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af96b7880d1---zerizafo.pdfIn PDF document text
    • http://www.kzhep.in.ua/wp-content/plugins/super-forms/uploads/php/files/pmp5g31t186kun8i69tifa3s36/3323269903.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn 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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ec85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC85 5128 bytes
SHA-256: 1a7cac2708ffc3e1cee85960384917d4866ecda8486c404637df4924a3a95f06
font_01_sfnt_off0000fe18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE18 12288 bytes
SHA-256: 25a872ca4ae702281434ac7d2a733e75f20a31898399b2db73cb734885dbfc3f