Malicious PDF — malware analysis report

Static analysis result for SHA-256 537ac25c666c1912…

MALICIOUS

PDF

82.7 KB Created: 2021-09-18 05:57:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: be60e1ed0a8aa99c631ed4aeab37f472 SHA-1: ecba0ddf5d61958e12f24a0f9ffb70a036ebaa9d SHA-256: 537ac25c666c1912ea677499f6665cff3495395238e5d31f9db996ae0814aa39
156 Risk Score

Malware Insights

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

This PDF file was identified as malicious by multiple heuristics and an ML classifier, with ClamAV detecting it as a phishing trojan. The document functions as a link farm, containing numerous URLs pointing to potentially compromised websites or disposable domains, suggesting an intent to lure users to malicious content or phishing pages. The presence of external URIs and link farms on compromised CMS uploads indicates a multi-stage attack vector.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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 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.
  • 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://cructi.ru/uplcv?utm_term=shut+up+app+for+android PDF link annotation
    • https://assignmentmart.com/ckfinder/userfiles/files/lijug.pdfIn PDF document text
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/1613e4d6205801---81845603549.pdfIn PDF document text
    • https://sukhayurveda.in/userfiles/file/miteginonujogimuxirodim.pdfIn PDF document text
    • https://www.numberoneporthill.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1614512b255442---21090472833.pdfIn PDF document text
    • http://velocimapper.com/webfiles/file/kizexivawozefotejovevoz.pdfIn PDF document text
    • https://zohopin.com/calisma2/files/uploads/folenoj.pdfIn PDF document text
    • http://festivaldeliteraturadepereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/161405c332629c---29324120829.pdfIn PDF document text
    • https://minlinart.com/archive/upload/files/kopexugemejetedudugovifud.pdfIn PDF document text
    • https://travels-ukraine.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ad3501c977---98068195546.pdfIn PDF document text
    • http://www.cavice.fi/tiedostot/files/56231835291.pdfIn PDF document text
    • https://www.willmarshelter.com/ckfinder/userfiles/files/gudusomuk.pdfIn PDF document text
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/16136f1e79a1d0---92277161921.pdfIn PDF document text
    • http://mybed.tw/uploads/files/202109180843558551.pdfIn PDF document text
    • http://unionnutritech.com/upload/files/55113669437.pdfIn PDF document text
    • https://kasihpaham.com/contents/files/lelifazamawukazuloz.pdfIn PDF document text
    • http://bezagsecurity.cz/userfiles/sexazegupagi.pdfIn PDF document text
    • http://banghetretunhien.com/media/ftp/file/18910784964.pdfIn PDF document text
    • http://baigeleather.com/userfiles/file/71236919876.pdfIn PDF document text
    • http://katela.net/userData/board/file/memigos.pdfIn PDF document text
    • https://snabavto.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137ad96c2ca5---1763329746.pdfIn PDF document text
    • http://mebelhotel.ru/userfiles/files/momojibi.pdfIn PDF document text
    • http://vinmexindia.com/uploads/71438954726.pdfIn PDF document text
    • http://daiichihr.com/uploads/news_file/kerixevifigofakil.pdfIn PDF document text
    • https://latrinquette.com/upload/editor/file/wutinideroxasowekiwewewa.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_off0000e084.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE084 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f89b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF89B 10424 bytes
SHA-256: 1c014c5c82dbc8f75a4088e7d451cb5fe6c2e0f3141ce31810ebdc190763e2bf
font_02_sfnt_off00011023.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11023 17316 bytes
SHA-256: 468938f7ac02754cb187e65db5a841afcf189a6f330c828b36b56d8ab08dbdb7

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