Malicious PDF — malware analysis report

Static analysis result for SHA-256 43a4418faef13280…

MALICIOUS

PDF

78.0 KB Created: 2021-09-23 10:14:01 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6993a97e63329f9693933a0fcc56c6b0 SHA-1: 5f49605743b8d3e03173d8a345d93d384d8df587 SHA-256: 43a4418faef13280fb85e91dfc81398530b8743ab25c4f6ea83aa376b3f03691
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The sample is a PDF containing embedded JavaScript and a large number of external URIs. Several heuristics indicate that these URIs form a link farm, with many pointing to PDF files hosted on compromised WordPress sites or disposable hosting. The ML classifier and ClamAV detection strongly suggest malicious intent, likely related to phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://krisoc.ru/uplcv?utm_term=send+doc+in+messenger PDF link annotation
    • https://himalmanpower.com/ckfinder/userfiles/files/bakejavi.pdfIn PDF document text
    • https://augsburger-dartliga.de/uploads/file/67683486268.pdfIn PDF document text
    • https://www.zaantraining.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16144b24131b70---6992561135.pdfIn PDF document text
    • http://www.performhabitat.fr/bundles/astadmin/js/ckfinder/userfiles/files/10781031924.pdfIn PDF document text
    • https://u-spot.biz/js/ckfinder/userfiles/files/39563271147.pdfIn PDF document text
    • http://riviera.az/userfiles/file/tazijusegari.pdfIn PDF document text
    • https://limsurempat.com/contents/files/wudowelategodifodu.pdfIn PDF document text
    • http://opakowania-loga.pl/zdjecia/fotki/file/dekugasuxopuxelaf.pdfIn PDF document text
    • http://www.octopus-quatuorvocal.com/ckfinder/userfiles/files/38109344545.pdfIn PDF document text
    • https://www.indee-r.fr/wp-content/plugins/super-forms/uploads/php/files/e4f3aa636c9e193c898458f7e2da14c0/debitexemide.pdfIn PDF document text
    • http://aaaexpressheating.com/userfiles/file/52868967834.pdfIn PDF document text
    • http://www.iamgoingto1996.com/wp-content/plugins/formcraft/file-upload/server/content/files/161423cc9cbd8e---47278679963.pdfIn PDF document text
    • http://antonio-pelella.eu/userfiles/files/jupofadukowijer.pdfIn PDF document text
    • http://smirna.pl/files/file/bepot.pdfIn PDF document text
    • https://www.smartfutureexpo.com/ckfinder/userfiles/files/45418480959.pdfIn PDF document text
    • http://thepokeluau.com/uploads/files/wufelim.pdfIn PDF document text
    • http://drukarnia-warszawa.pl/pliki/file/2826307397.pdfIn PDF document text
    • http://park-seversk.ru/other/js/ckfinder/userfiles/files/jiroz.pdfIn PDF document text
    • https://onhimalayas.com/ckfinder/userfiles/files/rowikikusin.pdfIn PDF document text
    • https://trompis-tondschungel.de/userfiles/file/46229327401.pdfIn PDF document text
    • http://mobilni-kadernictvi.cz/files/file/57686735382.pdfIn PDF document text
    • http://gps-tw.com/CKEdit/upload/files/zerupejijivigapo.pdfIn PDF document text
    • http://uptownfallschurch.com/uploads/files/94943891623.pdfIn PDF document text
    • http://goldmustang.com/files/files/63020055188.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_off0000cdad.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCDAD 10480 bytes
SHA-256: f5c4e9b43ccc33eb903e2fa4d2e76d46a0952232f4cf9478b4f10969546cc95d
font_01_sfnt_off0000e52b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE52B 17500 bytes
SHA-256: b97d6f40537bb44a15deebc1670665c0c01e4646799f7f99ae7e1fa14dc539e2
font_02_sfnt_off00011263.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11263 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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