Malicious PDF — malware analysis report

Static analysis result for SHA-256 535c43fa1dc23915…

MALICIOUS

PDF

82.6 KB Created: 2021-09-17 14:45:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 83b28f09f7c6abc8809bb6c7b2a9d878 SHA-1: e7cbe32fc5a2e42d859ee1332cf350c66216377d SHA-256: 535c43fa1dc239151d7b67615e3769aa50624942288d40b1bf8b33a4e66fa2d7
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external URIs and is flagged as a link farm, with several pointing to compromised CMS uploads. Embedded JavaScript is also present, suggesting potential for further malicious actions. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9911

Heuristics 7

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • PDF link farm points to compromised-WordPress upload storage medium PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM
    PDF contains multiple clickable links, across many distinct hosts, whose targets are random-slug files parked in the upload directories of vulnerable WordPress form plugins (FormCraft, Super Forms). This is the hallmark of the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains hosted on compromised sites. The PDF itself carries no exploit — the risk is the linked destinations.
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://pixomot.ru/uplcv?utm_term=bigo+live+mod+apk+unlimited+coins
    • http://ahdongjiu.com/upload_fck/file/2021-9-3/20210903070138309819.pdf
    • https://akvaguru.hu/user/file/fugubeba.pdf
    • http://friulanapanini.com/images/file/29899965346.pdf
    • http://patrick-vallot.com/upload/files/bawekul.pdf
    • https://www.willmarshelter.com/ckfinder/userfiles/files/sumazubegopuvirelubesano.pdf
    • http://slhospital.com/upload/fckeditor/file/31384714858.pdf
    • http://www.caslyn.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/161390e87809a5---65064041611.pdf
    • http://zdrowejaja.com/Upload/file/91530736679.pdf
    • http://studioarchperissinotto.eu/userfiles/files/36132568788.pdf
    • https://acconpriti.com/ckfinder/userfiles/files/gedaguzegixoxidafofagi.pdf
    • https://eric-parnes.shortex.com/ckfinder/userfiles/files/sojulijik.pdf
    • https://fasleh.net/Files/files/xosujofemeze.pdf
    • http://i-dron.cz/data/file/47465695265.pdf
    • http://dspec-car.com/js/upload/files/89512773503.pdf
    • https://sevsport.info/wp-content/plugins/super-forms/uploads/php/files/7a309f8e353ec56b8d172a8d360de4a7/57286747605.pdf
    • http://risme.vn/files/99177952463.pdf
    • https://ekransamara.ru/files/jenogemonipemikuzewoxara.pdf
    • http://agenziaimmobiliarecannavo.eu/userfiles/files/12995663837.pdf
    • https://www.hotel-palladium.gr/wp-content/plugins/super-forms/uploads/php/files/k7thj1srb1hgk7o663e4mkngbo/89680004057.pdf
    • http://tamtamphat.com/upload/files/gotejuzodujufini.pdf
    • http://nceed.kr/pds/userfiles/files/64836607554.pdf
    • http://aarogyamedico.com/userfiles/file/44432862738.pdf
    • http://minhquoc.vn/ckfinder/userfiles/files/lebinigulo.pdf
    • http://koreaseals.com/ckfinder/userfiles/files/26662517147.pdf
    • https://dauglita.lt/components/com_mijoshop/opencart/image/data/files/19827692618.pdf
    • https://tsegypt.com/file/84221623888.pdf
    • http://kientrucphatloc.com/upload/files/xumoredetej.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d914.bin
b3a6b9f1b59f904618cb16f6a47bceb08668b85e010435d929bfdc21dffa2c32
pdf-font-stream PDF embedded font (sfnt) at offset 0xD914 18864 bytes
font_01_sfnt_off00010a90.bin
f75b345b59d77647680f0a3c9966d64ba040a422746d393c22f0830691938123
pdf-font-stream PDF embedded font (sfnt) at offset 0x10A90 11068 bytes
font_02_sfnt_off00012435.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12435 16792 bytes