Malicious PDF — malware analysis report

Static analysis result for SHA-256 c850520a48f9667a…

MALICIOUS

PDF

87.4 KB Created: 2021-09-13 14:06:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: d089da03cb926d7199fe03edd613f2c1 SHA-1: f352edecb6b2b33a39073e7074fee39135d1b38f SHA-256: c850520a48f9667ae56ab7c8af2c842bfa95393fcbde648def3317c4c7c2ffef
104 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs pointing to compromised WordPress sites and disposable domains, suggesting a link farm designed to trick users into downloading a payload. The ML classifier strongly indicated maliciousness, and the presence of multiple external URIs and a link farm heuristic supports a phishing or malware distribution attack pattern. No scripts were extracted, but the overall structure and URL findings are indicative of a downloader.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9946

Heuristics 6

  • 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.
  • Visual download / call-to-action button lure low SE_DOWNLOAD_BUTTON
    Document contains a call-to-action phrase ('Click here to download', 'Download Now', etc.) — low-signal unless other findings point to a malicious workflow
  • 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://queure.ru/uplcv?utm_term=ai+bot+apk PDF link annotation
    • http://lncxjzxxw.com/upload_fck/file/2021-9-7/20210907153314563042.pdfIn PDF document text
    • https://trichynext.com/wp-content/plugins/super-forms/uploads/php/files/2a90be75edc710b05dc3404f5a104e39/wejopajimagaginolul.pdfIn PDF document text
    • http://baby-daycare.com/uploads/files/202109021823369618.pdfIn PDF document text
    • http://xpeedon.net/userfiles/file/20210906181543.pdfIn PDF document text
    • http://xn--2-140-swe8h.xn--p1ai/files/81680106229.pdfIn PDF document text
    • http://www.tobywells.org/media/fckdir/file/21446641955.pdfIn PDF document text
    • http://studiotecnicoarduini.eu/userfiles/files/refonizoxidegiw.pdfIn PDF document text
    • http://softtox.com/new/userfiles/file/52571335765.pdfIn PDF document text
    • http://personal.sut.ac.th/chantira/port/ckfinder/userfiles/files/97318541366.pdfIn PDF document text
    • http://psn-monolit.ru/img_file/files/vajikofilarodinewa.pdfIn PDF document text
    • https://vespaclubcagliari.com/userfiles/file/gupisagiranepu.pdfIn PDF document text
    • http://diakmelo.hu/ckfinder/userfiles/files/rediwefilewawegozezal.pdfIn PDF document text
    • http://www.groupementpecheduloir.com/ckfinder/userfiles/files/dotavesifape.pdfIn PDF document text
    • http://zjnep.com/ckeditor/ckfinder/userfiles/files/85431360380.pdfIn PDF document text
    • http://chiengthai.com/file_media/file_image/file/mevaloxajejuradatisodit.pdfIn PDF document text
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/2514dd304a966e9f6335ffd6499bc814/soditanafesu.pdfIn PDF document text
    • http://klwas.org/userfiles/images/file/366210938.pdfIn PDF document text
    • https://wanfutemple.urwaydesign.com/data/file/userfiles/files/18077648608.pdfIn PDF document text
    • https://handientu.vn/userfiles/file/nunirekodakudabejuwod.pdfIn PDF document text
    • https://alkirbilaw.com/userfiles/files/96643051335.pdfIn PDF document text
    • https://acrgruppe.de/userfiles/file/95768344460.pdfIn PDF document text
    • http://ladyqueen.it/userfiles/files/kutesomaw.pdfIn PDF document text
    • https://3drm.bg/uploads/pictures/files/lipavubetuwinu.pdfIn PDF document text
    • http://yaan121.com/uploads/files/202109040324256211.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613864b2745f5---tigipixonekoti.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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d0ac.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD0AC 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e8bd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE8BD 16132 bytes
SHA-256: 071bac7a3a90310621307d68123817e30fba7c89f9e5021c4391eb43bd8b9137
font_02_sfnt_off0000fe34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE34 9908 bytes
SHA-256: 628b61cb5a140c0b26940cc67a9fca27059fc96c24edec14ea579266c2069e40
font_03_sfnt_off000113fd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x113FD 23088 bytes
SHA-256: e2b9a91d3b1b254f3c46dc3b5ad9cb330605a2c0af1db104241162ff08f33d0e

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