Malicious PDF — malware analysis report

Static analysis result for SHA-256 841fc7d444cae6e1…

MALICIOUS

PDF

80.1 KB Created: 2021-09-22 16:26:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: f99a5a14c4a355f45fe29079826fe08f SHA-1: 77bb570283c02040acfc9a9e6d0734fa59c228b3 SHA-256: 841fc7d444cae6e184a1b99d8a46c204a3b6e4920d29c51576be1871571a38d9
166 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many of which are algorithmically generated and hosted on disposable domains, indicating a phishing or malware distribution attempt. The ML classifier and ClamAV detection strongly suggest malicious intent, likely to redirect users to malicious sites or download further payloads. No scripts were extracted, but the PDF structure itself facilitates the attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9981

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • PDF link to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://chcial.ru/uplcv?utm_term=social+studies+for+csec+textbook+pdf PDF link annotation
    • https://ags-car.com/upload/files/sedimen.pdfIn PDF document text
    • http://amako-ra.com/wp-content/plugins/super-forms/uploads/php/files/2b58738afee8f5e51275499ce4261a59/pekudonubefe.pdfIn PDF document text
    • http://theaterbuehne-schwandorf.de/userfiles/file/26310448138.pdfIn PDF document text
    • http://carraracucinecomponibilitrapani.it/userfiles/files/56489567450.pdfIn PDF document text
    • http://www.colegiometa.net/home/wp-content/plugins/formcraft/file-upload/server/content/files/1613d385c2d2de---69879228550.pdfIn PDF document text
    • https://tranduongauto.com/app/webroot/files/images/pages/files/73904262012.pdfIn PDF document text
    • http://abwmountvernon.com/uploads/files/fixubudejojedelimasikudu.pdfIn PDF document text
    • http://naasschoolofmotoring.com/fckeditor/userfiles/file/66320080025.pdfIn PDF document text
    • https://em.heephong.org/ethnicminorities/cmsadmin/ckfinder/files/72033366912.pdfIn PDF document text
    • https://tgvl.in/uploads/fck/files/dipuki.pdfIn PDF document text
    • http://sonnenheizung.ch/fckeditor/editor/images/file/foxakifuje.pdfIn PDF document text
    • http://vesimport.ru/userfiles/file/dazolumurewezujake.pdfIn PDF document text
    • http://restokrat.info/userfiles/file/91646150072.pdfIn PDF document text
    • http://fotografiafrancescosomma.com/userfiles/files/fujafufumifisivelu.pdfIn PDF document text
    • http://crm333.com/documentos/file/nosixalenufanazonovarujox.pdfIn PDF document text
    • http://redondoclassicburger.com/uploads/files/42547344739.pdfIn PDF document text
    • http://dominopark.pl/public/upload/ckfinder/userfiles/files/gowofanizebutir.pdfIn PDF document text
    • http://icaalliance.org/filespath/files/20210921170130.pdfIn PDF document text
    • http://qazaqbanki.kz/data/content/files/81169517383.pdfIn PDF document text
    • http://ovstav.cz/app/webroot/files/files/75957317347.pdfIn PDF document text
    • https://torbay.ru/images/uploads/file/29023854404.pdfIn PDF document text
    • http://assessmentinsight.com/ckfinder/userfiles/files/77658661207.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://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_off0000d4f5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD4F5 16968 bytes
SHA-256: 4d3b573bb929b6b17c04bb7ec81f3db3d94d51da9dafef2952c131a451c6ed44
font_01_sfnt_off0001011c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1011C 11016 bytes
SHA-256: 09cd1fedb6aff794c7087aa1f59434c55298f947f8a1455f02c7bbd4c4ad35ed
font_02_sfnt_off00011aa4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AA4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1