Malicious PDF — malware analysis report

Static analysis result for SHA-256 16671eb63cd059b7…

MALICIOUS

PDF

78.7 KB Created: 2021-09-18 13:16:00 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 2fdeb436a8f08fb560400ddbd5862bbf SHA-1: 214d7313e7684ba4e53f23a6fa63f6869cb9ad6b SHA-256: 16671eb63cd059b7a873de70aae5c6887f64a1ae5098edb7861866bb8a38acb3
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm containing numerous URLs, many pointing to compromised CMS uploads and disposable hosting. The PDF document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://schachverein-marchhoefe.ch/fcsr/news/upload/file/wejapunebisudinizeli.pdf
    • http://luckyassessoria.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1612eaa803978d---70861634719.pdf
    • http://studiogiovannone.com/userfiles/files/zuxuk.pdf
    • https://viadagio.be/userfiles/file/mokizus.pdf
    • https://guijek.com/userfiles/file/84293741619.pdf
    • http://ukicda.com/admin/fckeditor_upfiles/file/2021091414292980554.pdf
    • http://svs-pm.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131aca46bef7---livakinisipokakiluwusosev.pdf
    • https://podiummagazinenews.com/ckfinder/userfiles/files/wuzazubaz.pdf
    • http://ride.hu/images/uploads/files/sulavusemejukosopodekuba.pdf
    • http://kredoteka.ru/uploads/file/82580285483.pdf
    • https://buildingexpertsdirectory.com/ckfinder/userfiles/files/mofobuxumupibewiw.pdf
    • http://se-ty.ru/uploads/userfiles/file/lebuz.pdf
    • https://grandhotelbulgaria.com/userfiles/file/maranisezukukopo.pdf
    • https://barcelona-health.com/files/galeria/files/felob.pdf
    • https://www.lindopoint.it/wp-content/plugins/super-forms/uploads/php/files/52f989a0a1169bccba8afebf087873f9/muxejiziduwefitunovat.pdf
    • http://ebd.su/UFD/7623/files/merutaziwizopegijamo.pdf
    • https://relaxationplusmn.com/wp-content/plugins/super-forms/uploads/php/files/e3e2be2a9a70f708b7222ea1684475bd/sojexaladigurumisupazufas.pdf
    • https://vinaconexmec.vn/uploads/news_file/xitifufukeliwema.pdf
    • http://krukaiart.com/userfiles/files/vevewesilitonemap.pdf
    • http://mijneigenlift.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16142251750a6f---45561434847.pdf
    • http://stefanourso.com/public/userfiles/file/82279153988.pdf
    • https://reviewz.eu/app/webroot/files/userfiles/files/nelufatosilogutiwewaj.pdf
    • https://gujaratisamajparis.org/upload/files/22393712297.pdf
    • http://energy-labels.com/userfiles/file/52104251430.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/BvfzZFkJO3s/uplcv?utm_term=gmail+preview+pane
    • 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_off0000d2f5.bin
8e9d45684ee854fb7026d96a4dc1954679ecec3888c283c903e393e02aa8bca9
pdf-font-stream PDF embedded font (sfnt) at offset 0xD2F5 16784 bytes
font_01_sfnt_off0000fe32.bin
da06061c68994c33eae56f05f511498ec78b8f9eaee2b9e0e570713d8948a56e
pdf-font-stream PDF embedded font (sfnt) at offset 0xFE32 10216 bytes
font_02_sfnt_off00011511.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x11511 16792 bytes