Malicious PDF — malware analysis report

Static analysis result for SHA-256 a3d9cfdacfa7bccb…

MALICIOUS

PDF

82.0 KB Created: 2021-09-09 01:53:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 5b235a77bcc56021b12b670d2253fd42 SHA-1: 20127968bd5665f8e5a122338ff49b27fa9955d5 SHA-256: a3d9cfdacfa7bccbd3f0001c8335aca065c65673addf4dc7e97e0ef157ee41ce
156 Risk Score

Malware Insights

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

This PDF file was flagged by multiple heuristics as malicious, including a critical ClamAV detection and an ML classifier indicating a high probability of maliciousness. The heuristics indicate the PDF functions as a link farm, directing users to compromised WordPress uploads and other disposable hosting sites. The presence of numerous external URIs and link farm indicators suggests the primary purpose is to redirect users to potentially malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9846

Heuristics 6

  • 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.
  • 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=smart+wallpaper+app
    • http://ballarioarchitetti.eu/userfiles/files/vopolepotedo.pdf
    • http://gemcom.org/userfiles/file/55648159234.pdf
    • https://sintasyapi.com/img/userfiles/file/tamufapajator.pdf
    • https://themodernla.com/wp-content/plugins/super-forms/uploads/php/files/8fe787b6424a450e3af7d6b96a6aaf85/sidudegirediwubujufetad.pdf
    • https://coachtourbusrental.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137b4c869a91---49140600131.pdf
    • https://istanbularicilikfestivali.com/upload/ckfinder/files/vefitad.pdf
    • https://masini-de-ambalat.ro/images/userfiles/jagopefuvova.pdf
    • http://arcenevents.nl/site/upload/files/66854076563.pdf
    • https://xpress2.eu/ckfinder/userfiles/files/daninipejibep.pdf
    • http://coolscape.info/images/files/kejesudemuxifijigesisevu.pdf
    • http://botosani.ro/img/uploads/file/99187174489.pdf
    • http://detaycopymatbaa.com/userfiles/file/71917787211.pdf
    • https://kirmatas.com/userfiles/file/27032344589.pdf
    • http://aktifimmo.lu/userfiles/files/kapewepupisobasidevopila.pdf
    • http://giga.sk/storage/file/nivuf.pdf
    • https://777mto.com/contents/files/xowoju.pdf
    • http://greatwalledmond.com/ckfinder/userfiles/files/zozikamevem.pdf
    • http://www.ags-sib.ru/ckfinder/userfiles/files/puzenemiguxelezixipiwin.pdf
    • http://hiro-seiko.com/upload/files/27492495756.pdf
    • http://viprealestatebrokers.com/userfiles/files/jixelejixan.pdf
    • http://xn--80ackbssfuieecff0e8c.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/m256apcuif1l3ittd3uivpg582/52395517903.pdf
    • http://dworbieland.pl/userfiles/file/jugozutevom.pdf
    • http://holmeslawfirm-iowa.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/pupowilepojuvi.pdf
    • https://pisangmanis.com/contents/files/ziwefujuveduz.pdf
    • http://cnwt.mgo.cool/upfile/files/2021/09/06/11439674481.pdf
    • https://xanbiente.de/userfiles/file/zubolusekogesunikitabajo.pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000dd55.bin
d324696dcd900a38ba4ed8dc6c95c241b067f3a4dc6ccbbebf6b40aa73911c69
pdf-font-stream PDF embedded font (sfnt) at offset 0xDD55 10088 bytes
font_01_sfnt_off0000f3ef.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF3EF 16792 bytes
font_02_sfnt_off00010c01.bin
20486e71827b0f7253427b1e603ab347cbf2f272156747b2fa435059051cd7ca
pdf-font-stream PDF embedded font (sfnt) at offset 0x10C01 18116 bytes