Malicious PDF — malware analysis report

Static analysis result for SHA-256 31863023ec796c3a…

MALICIOUS

PDF

85.7 KB Created: 2021-07-05 04:08:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ba36c10fbf5de14cfd72bee04b5e2d48 SHA-1: acf48b3e273ef09f08183285e05a4cc288a960f2 SHA-256: 31863023ec796c3abddd7c081e7129afc935bc315549b0c5e1abaaf538a07ae0
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

This PDF file contains numerous links to compromised WordPress uploads and other disposable hosting sites, masquerading as a document about epiglottis swallowing problems. The ML classifier and ClamAV detection strongly indicate malicious intent, likely to redirect users to phishing or malware distribution sites. No scripts were extracted, but the PDF's structure and URL patterns are indicative of a link farm designed for malicious redirection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 7

  • 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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://atlasautoglass.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609dd7f7db081---7540367308.pdf
    • https://felix-schulze.biz/wp-content/plugins/super-forms/uploads/php/files/kkjvp2eqcer8748kddig4mql4u/vigujifusajusedi.pdf
    • https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/du2kd5qv7l0u509v3uofjct18r/zedixarabumilorawiba.pdf
    • http://www.alex-vasilkov.ru/images/wisdom/file/xupuzufoxarowiberokirelil.pdf
    • http://www.appsolutely.sg/wp-content/plugins/formcraft/file-upload/server/content/files/160a8bce4cff91---molusalejewobe.pdf
    • https://www.lorenzofranzone.it/wp-content/plugins/super-forms/uploads/php/files/1a05c3bac5b7a42b4c7b8342ca382eac/78005850011.pdf
    • https://juhaszautovill.hu/userfiles/file/noronisegoxosatuj.pdf
    • https://advancedcheckcashadvance.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b1e38e1c61d---xusizezenizuxopamuf.pdf
    • https://bruceautoservice.com/files/file/89567283920.pdf
    • http://ctyrkolky-gamax.cz/data/dokumenty/vabuxun.pdf
    • http://erfolgsapp.de/wp-content/plugins/formcraft/file-upload/server/content/files/160ad8c3fa6d33---fetadolelimunofoxeseterap.pdf
    • http://nicosiacaffe.it/file/11264000733.pdf
    • http://bioident.pl/photos_fck/file/53732007219.pdf
    • https://hoffmanowska.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160b6870546e2e---15577273879.pdf
    • https://ambulatorioveterinariosismondi.eu/file/71360637050.pdf
    • https://simovi.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1607e0f95acde6---76024498985.pdf
    • http://pferdefreunde-brueckenhof.de/sites/default/files/userfiles/file/12268826957.pdf
    • http://www.melloecastro.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607b792b0c644---lefekogumawunarexadu.pdf
    • http://odessahighschool1970.com/clients/7/70/70263b1be1b93b62200e198143f59f20/File/30075123694.pdf
    • http://raduzhniy.com/wp-content/plugins/formcraft/file-upload/server/content/files/160983c0ae974d---6285694941.pdf
    • http://ks4073.com/file_media/file_image/file/goxexetixurapov.pdf
    • http://apexnepaltravel.com/userfiles/file/20697165806.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=epiglottis+swallowing+problems
    • 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_off0000ed01.bin
a1d3f858f5738a91f54c6772141c15e5efcd3f6c9589038d03d94fa5e62b75c7
pdf-font-stream PDF embedded font (sfnt) at offset 0xED01 10804 bytes
font_01_sfnt_off000105b7.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x105B7 16792 bytes
font_02_sfnt_off00011dc9.bin
f3fc978c8c5ebea6b6aeb99ed7c65be1f9bf2f05443fc5928093f5eda9d2e41b
pdf-font-stream PDF embedded font (sfnt) at offset 0x11DC9 16984 bytes