Malicious PDF — malware analysis report

Static analysis result for SHA-256 3814b73f9d4847a7…

MALICIOUS

PDF

98.2 KB Created: 2021-06-29 02:50:39 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 71286cb5aee5be6b6080a4ae822c8b8d SHA-1: c1f245b23ce55d367f2f005d5796c1bf79048966 SHA-256: 3814b73f9d4847a77af94c080ab805894d5c5e0fc5c662b96851c7d1b6f528fe
96 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 compromised WordPress upload directories, indicating a link farm designed to redirect users. The ML classifier strongly flagged this PDF as malicious. The primary attack pattern involves leveraging these links to potentially deliver further malicious content or phish for credentials.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9964

Heuristics 5

  • 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://inwebjor.ru/uplcv?utm_term=messed+up+with
    • https://inchiriereelicoptere.ro/wp-content/plugins/formcraft/file-upload/server/content/files/1608ed4b8c6f3b---61795285139.pdf
    • http://grani-tonkogo-mira.ru/wp-content/plugins/super-forms/uploads/php/files/f63a2292669c45629644babdb0053fff/95944219444.pdf
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607261ffcc3bd---16593994987.pdf
    • http://villaturri.com/wp-content/plugins/formcraft/file-upload/server/content/files/160815cb19a10c---23773538869.pdf
    • http://www.northeastmarquees.com/wp-content/plugins/super-forms/uploads/php/files/e748467301b4bc046ab03ed0fffe0bea/mijufebedor.pdf
    • http://amdind.com/userfiles/file/66010724218.pdf
    • http://zoltysnieg.pl/pliki_wyswig/files/78684219721.pdf
    • http://ednak.com/wp-content/plugins/formcraft/file-upload/server/content/files/160befa300d181---11516659679.pdf
    • http://kids-ex.com/41346928582.pdf
    • https://terravistahometeam.com/wp-content/plugins/super-forms/uploads/php/files/08707800ac2de35b77d9685523c2e1f8/degolesaroxanomogewusekim.pdf
    • https://klcmekatronik.com/ckfinder/userfiles/files/dutepakogivexup.pdf
    • https://aduanaldelvalle.com/userfiles/file/jawelafuliximifuvubajozez.pdf
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606f4cb0c3bf2---39819391014.pdf
    • https://kvartira-zalog.ru/wp-content/plugins/super-forms/uploads/php/files/cba41a18638aea11954be0412aeaf135/84134220387.pdf
    • https://ceilford.org/wp-content/plugins/super-forms/uploads/php/files/bdaa5f4e71d293f14f38423967c88574/mopeletijinetutoxadupibov.pdf
    • https://certifiedmoversinc.com/wp-content/plugins/super-forms/uploads/php/files/f241fd651797513fddf2b4f850129e67/23346490726.pdf
    • http://www.psstrecno.sk/wp-content/plugins/formcraft/file-upload/server/content/files/160b39d3515fa2---kegefiwaveboga.pdf
    • https://vidolamerica.org/wp-content/plugins/super-forms/uploads/php/files/6c9f20b84502a5b76301a6e7cf442ccc/71833050329.pdf
    • https://lawpropertyconsultants.co.uk/wp-content/plugins/super-forms/uploads/php/files/phqdnllc6i4mhg0hfjb4bik6fb/nibebilamigetimesamodosek.pdf
    • https://alllegaltask.com/wp-content/plugins/super-forms/uploads/php/files/p3qobnt2c25gs14npmvikd6sjj/wogodurufewiboxutazek.pdf
    • https://414movement.com/wp-content/plugins/super-forms/uploads/php/files/69fc2fea856fb3b73d60f29146c5a356/nokivivebutaz.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_off00012063.bin
23c4d6820d64802759324061719b6c1997237ea3704bfbc22f2aa4b4f117370c
pdf-font-stream PDF embedded font (sfnt) at offset 0x12063 17160 bytes
font_01_sfnt_off00014d22.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x14D22 16792 bytes
font_02_sfnt_off00016539.bin
075f5ffe8082221998aff2e53c130604a32201c44a748f447663e738b905a49c
pdf-font-stream PDF embedded font (sfnt) at offset 0x16539 10136 bytes