Malicious PDF — malware analysis report

Static analysis result for SHA-256 25fa5551dde9cf45…

MALICIOUS

PDF

93.0 KB Created: 2021-09-08 19:09:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 4b80d217b95894c7931fd84e81f0754f SHA-1: 895a76c94ddc857dd9cc1f280f0dfb6eb85b5a8c SHA-256: 25fa5551dde9cf4546a4b5b6b8e3f8deee0a15c6baeda3f1e5183cbd4dd59c56
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to numerous external URLs. Several of these URLs point to compromised WordPress upload storage, suggesting a tactic to host malicious content on seemingly legitimate but compromised websites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 http://bigbazar.cz/is/images/FCKeditor/File/51074559136.pdf In PDF document text
    • http://thesecurityguardunion.ca/userfiles/files/komoduw.pdfIn PDF document text
    • https://www.tai.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161384983d37b3---80427805741.pdfIn PDF document text
    • http://hkxhjfc.ltd/uploads/files/20210904073808.pdfIn PDF document text
    • https://metrosecuritynepal.com/assets/userfiles/files/73352391670.pdfIn PDF document text
    • http://imobiliariaimperio.com/files/files/sejazafuneg.pdfIn PDF document text
    • http://slxiang.com/v15/Upload/file/202192147288070.pdfIn PDF document text
    • http://pscemetery.com/userfiles/file/50591374214.pdfIn PDF document text
    • http://kleinschadenexperte.de/userfiles/file/10251852397.pdfIn PDF document text
    • http://homeopathyhk.com/files/zatoj.pdfIn PDF document text
    • http://pm-property.pl/userfiles/file/neluzovidejadamisos.pdfIn PDF document text
    • https://juhaszautovill.hu/userfiles/file/99153970280.pdfIn PDF document text
    • https://tractorpulling-emmeloord.nl/upload/file/23845150859.pdfIn PDF document text
    • https://volnynaklad.cz/data/file/65702220912.pdfIn PDF document text
    • https://lisacutler.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613297b89b6d5---82545678447.pdfIn PDF document text
    • http://www.sanruou.com/app/webroot/uploads/files/zariro.pdfIn PDF document text
    • http://cdenito.net/userfiles/file/rifazitatutiv.pdfIn PDF document text
    • http://nuocmambason.com/upload/fckimagesfile/dbdb682f6b450cb57b798f3379b6d476.pdfIn PDF document text
    • https://shrmivirtual.org/wp-content/plugins/super-forms/uploads/php/files/9872d1dc3967e348dd800e78552f4352/pajezowamipuvapa.pdfIn PDF document text
    • https://kiptep.ru/file/87546581236.pdfIn PDF document text
    • https://brahmagnanam.org/fck_uploads/file/50297055331.pdfIn PDF document text
    • http://dwallacelaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/96589599385.pdfIn PDF document text
    • https://kalyna.ua/sites/default/files/userfiles/file/51292389256.pdfIn PDF document text
    • https://mps-india.com/userfiles/files/99521787062.pdfIn PDF document text
    • http://rnralpha.cz/res/file/tewur.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=universal+plumbing+code+pdfPDF link annotation
    • 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_off00010858.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10858 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001206f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1206F 11180 bytes
SHA-256: da4b44534524fa343d6c6b2c0d8ce60f9bf8bf87038d1cfc7600c520b13b3900
font_02_sfnt_off00013a23.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A23 16808 bytes
SHA-256: 3fd72c40d184d03e9f8de011a428289a2dcc35833bdc5968555389983af62810