Malicious PDF — malware analysis report

Static analysis result for SHA-256 a9cc443e762438c5…

MALICIOUS

PDF

83.5 KB Created: 2021-08-24 20:17:29 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 61f31486498bdd4eea39ef3851703f21 SHA-1: d862abc34344db7b6026ca37c608a589f4e9e90c SHA-256: a9cc443e762438c57f2b4d219952fcca2547afbcee8cf434cd0cfe540e541b10
156 Risk Score

Malware Insights

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

The PDF contains a large number of external links, many pointing to other PDF files hosted on compromised WordPress sites or disposable domains. This suggests the document is part of a link farm, likely for SEO poisoning or to distribute further malicious content. ClamAV detection and ML classification strongly indicate malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9978

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://medvor.ru/uplcv?utm_term=chapter+18+chemical+bonds+answer+key
    • https://texigo.tw/upfile/files/2021/07/09/44886214550.pdf
    • https://sluganarodu.org/userfiles/files/mesegexo.pdf
    • https://businesslife.com/content/file/jebidarugidad.pdf
    • https://www.icslights.com/wp-content/plugins/super-forms/uploads/php/files/2268bd7b5ecae9de803a3621c464bf3a/mobamalinuw.pdf
    • https://www.napariverinn.com/wp-content/plugins/super-forms/uploads/php/files/9a67028a747fb944d801eddea76a8c43/dubipelepuwexisaxulikatet.pdf
    • http://toeicspeaking.net/_UploadFile/Images/file/jojemulezabose.pdf
    • https://goldenparadisestsimons.com/wp-content/plugins/super-forms/uploads/php/files/ffd4194aa121832c27ca66ba25f652df/nusudifuzowosuxesoruvolif.pdf
    • http://livestreaming.group/wp-content/plugins/super-forms/uploads/php/files/pd6dbf91bcejt0k5uk1r0a57g8sk8ld1/93120047667.pdf
    • https://diversified-nj.com/wp-content/plugins/super-forms/uploads/php/files/3fe313e68ce28c48a54b973088e5d880/21962024265.pdf
    • http://n2nlah.org/UserFiles/file/54976272895.pdf
    • https://genesisbehaviorcenter.com/wp-content/plugins/super-forms/uploads/php/files/944c29c1a3d5e7992f97374f7a524d07/3326056751.pdf
    • http://asustainable.com/global/file/tujakixume.pdf
    • http://www.hollyskauaicondo.com/wp-content/plugins/formcraft/file-upload/server/content/files/160af7c78d1eaf---vojixetemusufute.pdf
    • http://atlantichomeportugal.com/wp-content/plugins/formcraft/file-upload/server/content/files/16094d5922838a---64863200626.pdf
    • https://braviengenharia.com.br/wp-content/plugins/super-forms/uploads/php/files/gpi500a7jh1jf1n6t46bm4u4c5/finebavetuvivu.pdf
    • http://ranjitabiswas.com/userfiles/files/jinisosesak.pdf
    • https://artbynela.com/uploads/file/faritola.pdf
    • https://china-glass-mosaic.com/userfiles/files/20210702_191636.pdf
    • https://leunamgroup.com/wp-content/plugins/super-forms/uploads/php/files/fd2d0415ac682e4e78ee1eb1dab1d313/kelun.pdf
    • https://netpage.info/userfiles/file/jitifitepogaso.pdf
    • http://irinabailey.com/upload/files/lapebulopeweram.pdf
    • https://e-uchebnici.com/img/file/lapavufiduvan.pdf
    • https://karinbentum.nl/uploads/file/lixonazozapivuwezonap.pdf
    • http://www.orhancoskun.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606cc406238b2---19927122001.pdf
    • http://brighterhealthcare.co.uk/wp-content/plugins/super-forms/uploads/php/files/5jk217dgk7jqnvqf9chfc1usbe/wifufumidufotinenal.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_off0000e04d.bin
837e8d047e3422f53111684c7ac1765fabc25750cb16255f5dc037cda8803e3e
pdf-font-stream PDF embedded font (sfnt) at offset 0xE04D 16660 bytes
font_01_sfnt_off00010bcb.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10BCB 16792 bytes
font_02_sfnt_off000123e2.bin
dfc91ad2a99d806dbe5a39b02501210704ffc4c0ac11d4e1b013eb73d64d0103
pdf-font-stream PDF embedded font (sfnt) at offset 0x123E2 11500 bytes