Malicious PDF — malware analysis report

Static analysis result for SHA-256 81f650ab9a38fc1c…

MALICIOUS

PDF

74.6 KB Created: 2021-09-23 12:50:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: d2c24466962bcf3b80ef9d58b4fe3445 SHA-1: 7e901ede69ee030a7879c4afbd0a3f4661b999b6 SHA-256: 81f650ab9a38fc1c56e57408e2024f6eb197ec6fe942586cf64e8aa07783ab44
164 Risk Score

Malware Insights

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

The PDF contains multiple heuristics indicating malicious intent, including ML classification and ClamAV detection as a phishing trojan. It also features a 'download button' lure and numerous links to compromised websites, suggesting an attempt to trick users into downloading malicious content. The embedded URLs and the nature of the heuristics strongly suggest a phishing or malware distribution campaign.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9963

Heuristics 7

  • 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.
  • 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://coretry.ru/uplcv?utm_term=words+that+start+with+ch+but+sound+like+k
    • http://thenext.pk/userfiles/files/32456569712.pdf
    • http://highdeal.linkeo.net/ckfinder/userfiles/files/puzokivalanoselo.pdf
    • https://adci.vn/data/upload/file/82862523795.pdf
    • http://www.como-grup.ro/fisiere/file/newenapupikazufokuna.pdf
    • https://sledovani2.gpshlidac.cz/www/userfiles/files/84203177999.pdf
    • http://sarljarry.fr/userfiles/file/1023622678.pdf
    • http://www.dnevi-sekretarjev.eu/wp-content/plugins/formcraft/file-upload/server/content/files/16143860f519d6---komaxusuzopilemenava.pdf
    • https://nacionalequipamentos.com/ckeditor/uploads/files/64870848781.pdf
    • https://vnmmalta.com/userfiles/file/gututufapisofabufavup.pdf
    • http://banglenhospital.com/UserFiles/File/tunuwedawerevu.pdf
    • http://quangcaovuanh.com/vietkiendo/upload/file/xuzatenave.pdf
    • https://www.revistadefiesta.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614091f86b682---pilom.pdf
    • https://frontiermyanmar.com/sites/all/libraries/ckfinder/userfiles/files/22690713226.pdf
    • https://commonwealthsportsawards.com/userfiles/file/nedejawuwuvuzitutulozesa.pdf
    • https://skyfireconsulting.com/wp-content/plugins/super-forms/uploads/php/files/mhdmptaumegde89t52u0tjqsa7/padepanitidikudulibi.pdf
    • https://permargi.com/files/galeria/files/64693324561.pdf
    • http://captainkillmite.com/uploads/files/202109021537415737.pdf
    • http://vedepcuaem.com/luutru/files/fasovidobota.pdf
    • http://bangladeshceramicsociety.com/uploads/editor/files/42097771885.pdf
    • http://refpecsbelvaros.hu/kepek/files/24141286410.pdf
    • http://brandorbit.in/userfiles/file/boxopubufewopumorinolaluf.pdf
    • https://threadworx.com/thread/admin/uploads/file/dipixibekozod.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_off0000bec0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xBEC0 16792 bytes
font_01_sfnt_off0000d6d2.bin
3594a40749058d621e3673e2248d2e6a2b9f3b65f032e0bb90c02fb12c630fae
pdf-font-stream PDF embedded font (sfnt) at offset 0xD6D2 17488 bytes
font_02_sfnt_off000103c2.bin
de4be459fd3bf6b22356a363b64c3f413455f09147c849c523894ad8d11e05e6
pdf-font-stream PDF embedded font (sfnt) at offset 0x103C2 10876 bytes