Malicious PDF — malware analysis report

Static analysis result for SHA-256 38c61c3da3bdf8f4…

MALICIOUS

PDF

74.7 KB Created: 2021-02-27 16:43:09 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-05-23
MD5: 4d4df35be39a51c7f779e36817370b8f SHA-1: 5c86cbc9c360333b74839216d4e9e85d1fdbe820 SHA-256: 38c61c3da3bdf8f43148a2ed3f35251c794c13d8fbc10b36932e454e9426c020
126 Risk Score

Malware Insights

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

The PDF file was flagged as malicious by ML classifiers and ClamAV, indicating a high likelihood of malicious intent. The document body, though partially garbled, suggests a lure related to 'classroom rules'. The presence of external URIs, particularly those on disposable hosting and with UTM parameters, strongly suggests these are used to redirect users to malicious sites for further exploitation or phishing. No scripts were extracted, but the PDF structure and embedded URIs are indicative of a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • 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://dugedepap.ru/wix?keyword=reglas+del+salon+de+clases+para+imprimir+pdf PDF link annotation
    • http://xorabawik.medianewsonline.com/how_to_repair_water_pump_leak.pdfIn PDF document text
    • https://cdn.sqhk.co/rapovebakeb/hFPrp78/hudito_happy_hockey_days.pdfIn PDF document text
    • http://gisoboxizaza.mygamesonline.org/94273354323.pdfIn PDF document text
    • http://jaxebememapi.iblogger.org/what_is_my_race_if_im_black.pdfIn PDF document text
    • https://cdn.sqhk.co/purilusevike/jaje7xE/wheels_on_bus_go_round_and_round.pdfIn PDF document text
    • https://cdn.sqhk.co/zalivelo/icjbuhj/skinstore._com_customer_service_phone.pdfIn PDF document text
    • https://cdn.sqhk.co/jesisuvov/bLIAsjg/hd_tumblr_wallpaper_for_laptop_full_screen.pdfIn PDF document text
    • https://cdn.sqhk.co/dokukavifig/ogdBNhj/masaredixumefavokiga.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://devuzobek.rf.gd/radio_bodor_sunda_cangehgar.pdfIn PDF document text
    • http://zakuvusebaj.epizy.com/62733133165.pdfIn PDF document text
    • http://kivozusemu.atwebpages.com/what_is_the_maximum_weight_for_a_baby_car_seat.pdfIn PDF document text
    • http://vexabimumemig.atwebpages.com/how_to_reset_my_time_warner_remote_control.pdfIn PDF document text
    • http://penisofitomi.epizy.com/pefonutatize.pdfIn PDF document text
    • http://jopodovijub.rf.gd/nasabadebatefalatawunaw.pdfIn PDF document text
    • http://kibululugavi.epizy.com/zomitagazegewujujopamaj.pdfIn PDF document text
    • http://kutezowifemiwe.epizy.com/dijazanavatosepadipakefe.pdfIn PDF document text
    • http://safodur.epizy.com/lufiwibijulidubafe.pdfIn PDF document text
    • http://gidazajizi.rf.gd/smoothie_recipes_with_frozen_fruit_and_peanut_butter.pdfIn PDF document text
    • http://sozidimimu.rf.gd/cells_alive_meiosis_phase_worksheet.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_off0000e4b8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE4B8 5484 bytes
SHA-256: 41d5760cf655ac2f174a94609f4737b878b3547c6748a8e0f1eeda71167e7c2e
font_01_sfnt_off0000f755.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF755 11196 bytes
SHA-256: 7ea398273f8f0c0ff7973dd08235f27d16f023a0a0c53be7115f301a2dd13235

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