Malicious PDF — malware analysis report

Static analysis result for SHA-256 58b809bbddf2c98b…

MALICIOUS

PDF

80.6 KB Created: 2021-05-24 23:40:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-21
MD5: 64b14e67d8e9d6a0c403b4020f91b124 SHA-1: 75c56d1911dd0ca783d16af28674ec361a77728d SHA-256: 58b809bbddf2c98becc47ca8733ac2cfa1cbfb42a38c1f440af8ebc7f6ce649d
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, with a critical heuristic identifying it as a 'PDF_SEO_LINK_FARM'. One of the primary external links points to 'https://jacksth.ru/strik', which is suspicious. The ML classifier and ClamAV also flagged this PDF as malicious, indicating a high likelihood of malicious intent. The document body contains garbled text but includes a reference to 'wkhtmltopdf', suggesting it was generated by a tool rather than being a legitimate document.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://jacksth.ru/strik?utm_term=what+is+the+cheapest+csgo+knife PDF link annotation
    • https://lariwajiko.weebly.com/uploads/1/3/4/3/134316624/jogupu.pdfIn PDF document text
    • https://ruxevikupasej.weebly.com/uploads/1/3/4/6/134663562/tabonitavabevejegope.pdfIn PDF document text
    • https://nipawivas.weebly.com/uploads/1/3/2/6/132680981/9523671.pdfIn PDF document text
    • https://muvekova.weebly.com/uploads/1/3/5/3/135394778/fojefa.pdfIn PDF document text
    • https://zoluvurodozi.weebly.com/uploads/1/3/0/7/130776250/pijavubasaxuv_sapadomupibekum.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • https://s3.amazonaws.com/sorapobuk/bamipunekoberi.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9ceb27ea-495f-4ddc-b718-ed4c0bb5189d/robertshaw_thermostat_9400_manual.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6db708fd-1b64-42b4-8b34-41dd4f4a9529/how_can_you_fix_a_blown_head_gasket.pdfIn PDF document text
    • https://s3.amazonaws.com/fezenur/fivasivoludixu.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9f23f2df-cc92-4f2d-b67d-9989b91cfc62/5882403730.pdfIn PDF document text
    • https://s3.amazonaws.com/fidefofudi/51299984510.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/d275c612-760a-4273-87b5-2543b963ab6b/3503657703.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/00e069fe-2c09-4478-9472-60301068f76a/verb_list_a-z.pdfIn PDF document text
    • https://s3.amazonaws.com/vuxalirudidel/betolofemejuzaxeropaza.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/fd14516e-cee4-4b94-a4c5-3c6a036f12d2/33676038455.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/9cdb7aec-6b8f-477d-a6d4-0e651fbb05c2/tepijapikumerobefefij.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/3d257407-9d7d-46b1-a758-950132acaa8d/excel_urgent_care_spring_cypress.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/898b2ce9-2d74-4525-bce4-82ae50138afd/tatalazedufira.pdfIn PDF document text
    • https://s3.amazonaws.com/xakajoziwibi/92236155732.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/6e7fba1d-701a-4a76-88e9-f01cee56d1ec/intermediate_microeconomics_with_calculus_study_guide.pdfIn PDF document text
    • https://s3.amazonaws.com/wunojipu/university_english_vocabulary_list.pdfIn PDF document text
    • https://s3.amazonaws.com/mivokozibu/86256044447.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/a49c86ba-946e-48b3-b07d-e185fce42135/piluxizilewifetogi.pdfIn PDF document text
    • https://s3.amazonaws.com/tumuzu/how_do_i_fix_my_mini_sewing_machine_not_stitching.pdfIn PDF document text
    • https://s3.amazonaws.com/nabifovu/blood_pressure_medication_recall_list.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/2866b4ab-2287-4998-9f2d-c1cd7b59afbd/quick_guide_to_install_hp_laserjet_1100_on_windows_10.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e6ef6812-0840-4096-a1b1-ae9ef78e368c/46643673897.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f632.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF632 5228 bytes
SHA-256: 3b488057993d326a5e52a238bc2c99c68b838527ec99fe0d208d99d0707e65d0
font_01_sfnt_off00010814.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10814 13176 bytes
SHA-256: 1f351a1d2b86ce811e2e15eee69b05ce06c4e6c0bdff1f8132e3e0899beebd81