Malicious PDF — malware analysis report

Static analysis result for SHA-256 c173a7929a15e436…

MALICIOUS

PDF

76.1 KB Created: 2021-09-17 02:38:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: f4b14af44f5d1a60184104140c4e0d4f SHA-1: 84f8a241c0e39d37a8b25bf34e9e3ef4fdda7f36 SHA-256: c173a7929a15e4367fde7e5ce20c3af5afef6b52d3f8bc8fbd0dbd29a1b46c7e
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which are hosted on disposable domains and appear to be part of a link farm, a common tactic for phishing or distributing further malware. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' strongly suggests a malicious intent to redirect users to potentially harmful sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9908

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://catamma.ru/uplcv?utm_term=friend+request+2020+watch+online+free PDF link annotation
    • https://kujainspectors.com/candyticket/uploads/page_images/files/zuketisebisad.pdfIn PDF document text
    • https://natinsel.com/imagenes/file/wapusisurosod.pdfIn PDF document text
    • https://purefeeling8.com/data/file/ditemiririkituxevexajow.pdfIn PDF document text
    • https://digireg.li/upload/25695492116.pdfIn PDF document text
    • http://birizgardenhotel.com/userfiles/file/pazozukuxuporasirubifudo.pdfIn PDF document text
    • https://sdhouse.info/ckfinder/userfiles/files/5690292620.pdfIn PDF document text
    • https://qian-ho.com/upfiles/editor/files/gakugavaguzitizus.pdfIn PDF document text
    • http://istanbulballoons.com/ckfinder/userfiles/files/71584061472.pdfIn PDF document text
    • http://35ct1.com/images/ckImageFiles/files/46922904793.pdfIn PDF document text
    • https://aljazeerahdrilling.com/userfiles/files/51728449855.pdfIn PDF document text
    • https://xyoaa.org/sites/default/files/files/xivabemuw.pdfIn PDF document text
    • http://chnli.tw/CKEdit/upload/files/woneweminotexetuwawezoda.pdfIn PDF document text
    • http://paulgraphics.paulsfashion.in/files/vizowatuj.pdfIn PDF document text
    • http://www.gleason.com.au/application/third_party/ckfinder/userfiles/files/putiteru.pdfIn PDF document text
    • http://www.mezmat.ru/ckfinder/userfiles/files/zigilozakurezulirabek.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613a827936c7d---kiliz.pdfIn PDF document text
    • https://holcom-wd.com/webroot/img/files/zizupotop.pdfIn PDF document text
    • http://ekotop.eu/userfiles/file/zepuveru.pdfIn PDF document text
    • https://vhssirimpanam.org/ckfinder/userfiles/files/baguwiredamixo.pdfIn PDF document text
    • http://ranjitabiswas.com/userfiles/files/32911530113.pdfIn PDF document text
    • http://j-club.eu/userfiles/file/29112439852.pdfIn PDF document text
    • http://krallarintavugu.com/upload/file/figije.pdfIn PDF document text
    • http://delfosventures.com/userfiles/files/tupoba.pdfIn PDF document text
    • https://iamluno.com/wp-content/plugins/formcraft/file-upload/server/content/files/161379a9f48a3b---26227402862.pdfIn PDF document text
    • http://skkouty.cz/ckfinder/userfiles/files/nirusimum.pdfIn PDF document text
    • http://sicompk.com/survey/userfiles/files/20140290856.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_off0000c57f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC57F 16696 bytes
SHA-256: 434fd7b02866310725c6443d6b3da2171d33172b28b0f4fb666c50b3dfe5e466
font_01_sfnt_off0000f047.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF047 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off0001085e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1085E 11124 bytes
SHA-256: 842fd50c636a8d174089f105cf3df282e93add72803b7485f175b451db3b3182