Malicious PDF — malware analysis report

Static analysis result for SHA-256 b239641ab5733e53…

MALICIOUS

PDF

72.0 KB Created: 2021-09-27 01:45:27 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 43691f834cf4c0a8485f15209f21bd8b SHA-1: ceb0de0b466f3a4976f6eb64d409ed9f4f3ac676 SHA-256: b239641ab5733e530eeda8eeeb2f471280d2eabe2f176fe8b59347dcc94f7733
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, with numerous distinct domains hosting PDF files, suggesting an attempt to distribute malicious content or phish users. While no scripts were directly extracted, the PDF structure and heuristic firings strongly suggest it's designed to redirect users to potentially harmful external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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 http://gnatowski.pl/attachments/file/62952629408.pdf In PDF document text
    • http://www.enjoyvaltellina.it/admin/ckfinder/userfiles/files/31381576094.pdfIn PDF document text
    • http://zaun-produzent.de/userfiles/file/79677969697.pdfIn PDF document text
    • https://masini-de-ambalat.ro/images/userfiles/80253572600.pdfIn PDF document text
    • http://gsxr.hu/userfiles/file/9802486891.pdfIn PDF document text
    • http://www.drivingschool-brno.cz/files/files/55351798295.pdfIn PDF document text
    • https://zenithoverseas.com/assets/userfiles/files/68091120135.pdfIn PDF document text
    • http://cmsrecuperocrediti.it/images/file/90370401813.pdfIn PDF document text
    • http://www.otevrenysklep.cz/ckfinder/userfiles/files/7455561679.pdfIn PDF document text
    • https://shen-su.eu/gfx/userfiles/files/12423950778.pdfIn PDF document text
    • http://lobanowscy.pl/userfiles/file/xiruximobus.pdfIn PDF document text
    • https://www.getfitcrew.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f81717535d---fatazi.pdfIn PDF document text
    • http://cungcapbaoduongcuanhatban.com/upload/files/16831051955.pdfIn PDF document text
    • http://cambresisemploi.fr/ckfinder/userfiles/files/malokativuwiperanirugane.pdfIn PDF document text
    • https://autoandtruckrepair.net/nbloom/fckuploads/file/nurutesizojoridapojax.pdfIn PDF document text
    • http://studio-castiglioni.com/userfiles/files/41898583824.pdfIn PDF document text
    • http://toptoptraining.ru/img/upload/file/nelid.pdfIn PDF document text
    • https://rafautama.com/uploads/file/nosemonorikalukamedowu.pdfIn PDF document text
    • http://tingchucontrol.com/Uploadfiles/files/numabatizajipune.pdfIn PDF document text
    • https://www.dogandemir.av.tr/paketler/ckfinder/dosyalar/files/1877543962.pdfIn PDF document text
    • http://ylpcl.com/ckfinder/userfiles/files/vijil.pdfIn PDF document text
    • http://www.ciesol.es/ckfinder/userfiles/files/62646813750.pdfIn PDF document text
    • http://sportservistocik.cz/UserFiles/File/zujigajatifuzodorat.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/fzgW7-mxBc0/uplcv?utm_term=turn+off+talkback+motorolaPDF link annotation
    • https://www.thc.gda.pl/ckfinder/userfiles/files/33522047181.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_off0000b56e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB56E 10400 bytes
SHA-256: 884c0f2178fd068051d5169a801535b5fce56d78800a91017f28e6c7b5714b77
font_01_sfnt_off0000ccfc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCCFC 17520 bytes
SHA-256: bc996b84bd15ed2f0f6510446d479f0dd69b340df119e9be2b35f7c4faa1efa1
font_02_sfnt_off0000fa05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFA05 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1