Malicious PDF — malware analysis report

Static analysis result for SHA-256 71b2818aa357e3eb…

MALICIOUS

PDF

80.9 KB Created: 2021-09-11 13:46:45 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: dd3f8892100e1261958821cab27862c6 SHA-1: 7b049b25fcb34f8c36af74da826e69e9c7f9a482 SHA-256: 71b2818aa357e3eb37ae1ae831e9a4f79c6c8bd3002fe906d96870cb1ade1a18
156 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains numerous external URIs and link farms pointing to various domains, many of which appear to be compromised or disposable hosting. The primary function seems to be redirecting users to external content, likely for phishing or to download further malicious payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://archism.ru/uplcv?utm_term=run+android+emulator+on+android PDF link annotation
    • https://rosenstein.lu/userfiles/files/46035823249.pdfIn PDF document text
    • http://rgn2u.com/userfiles/files/86453959278.pdfIn PDF document text
    • https://sierrainstruments.cn/fckeditor/editor/filemanager/connectors/php/fckeditor/upload/202109/file/59483210644.pdfIn PDF document text
    • http://spokoino.ru/i/upload/files/fatomosiwumaf.pdfIn PDF document text
    • http://pes.edu.mn/ckfinder/userfiles/files/puwebiru.pdfIn PDF document text
    • http://donahoelawfirm.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/riroxewodaxor.pdfIn PDF document text
    • https://braintreeclinics.com/app/webroot/img/files/zurupemupibew.pdfIn PDF document text
    • http://pietrek.com/MARCUS/files/file/53085551224.pdfIn PDF document text
    • https://macleanpinesdrivingschool.com.au/wp-content/plugins/super-forms/uploads/php/files/69bcb1c9dde3f8e027e539c86a5cd768/15423403764.pdfIn PDF document text
    • https://www.sussexweddingservices.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16132669b27ee9---85156686872.pdfIn PDF document text
    • https://stealthwindow.tw/uploads/files/202109041704068685.pdfIn PDF document text
    • http://thrifty-uy.com/files/others/68108754455.pdfIn PDF document text
    • http://termosystem.pl/userfiles/file/8516551759.pdfIn PDF document text
    • https://b2b-intelligence.it/uploads/file/tuwomori.pdfIn PDF document text
    • https://facades-et-traditions.com/actualites/file/jipobej.pdfIn PDF document text
    • https://www.winsum.frl/ckfinder/userfiles/files/wixexuroxureja.pdfIn PDF document text
    • https://purpleleafestatebuyers.com/wp-content/plugins/formcraft/file-upload/server/content/files/161320fbd5413d---goxujebolud.pdfIn PDF document text
    • http://redeyeldn.com/userfiles/file/87655491834.pdfIn PDF document text
    • https://www.ogblfrontaliers.fr/wp-content/plugins/super-forms/uploads/php/files/u8kls8pbul6v1uo4b1f0dc267a/nuremewu.pdfIn PDF document text
    • https://clove7.com/userfiles/file/11411680648.pdfIn PDF document text
    • http://grapes4u.ca/sites/all/sites/grapes4u.ca/files/30486811854.pdfIn PDF document text
    • http://myslizdrave.com/soubory/xerevovalele.pdfIn PDF document text
    • https://ginecologmuresan.ro/ckfinder/userfiles/files/moxilipixab.pdfIn PDF document text
    • http://protech.com.ng/wp-content/plugins/formcraft/file-upload/server/content/files/16133ae3633ca1---60298081894.pdfIn PDF document text
    • http://bn-biz.com/userData/board/file/kemejavurifutepinaka.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_off0000d878.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD878 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f08a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF08A 17700 bytes
SHA-256: a033e4d4ae0b831ad052dc5b4e9d2403d7a777ab827c24dcaea3638c3cf3beba
font_02_sfnt_off00011e63.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11E63 10388 bytes
SHA-256: a4779a526f2a14618f0ad4ba4d7990aa8944562561b49182e7c194b383c13cf8