Malicious PDF — malware analysis report

Static analysis result for SHA-256 8144ac8b861e1931…

MALICIOUS

PDF

91.3 KB Created: 2021-08-19 13:50:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 51da800d3274997c161c736e45805933 SHA-1: 0e4ad4d1aab6a28156154a9effaba634e7105c97 SHA-256: 8144ac8b861e19317fc5690060a9f2403840fabfb38e2b5933489bd687a4558a
156 Risk Score

Malware Insights

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

The PDF was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised CMS upload directories or are part of a link farm hosted on disposable domains. The primary function appears to be redirecting users to external, potentially malicious sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9970

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 http://triatlonbizuterie.cz/sites/default/files/file/50090858163.pdf
    • http://thuephotocopytaihanoi.com/upload/files/18928431091.pdf
    • https://fietenhaardenenkachels.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1608d24cbefed3---36409298442.pdf
    • http://a-range.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1611e2142efec5---36265641079.pdf
    • https://themodernla.com/wp-content/plugins/super-forms/uploads/php/files/14efb9f98d0ba0748ddc90965e0c2986/96697069183.pdf
    • https://commonwealthsportsawards.com/userfiles/file/biterejidesaso.pdf
    • http://sparkpro.lv/content/file/zikuxinuvon.pdf
    • https://www.partyshuttlebus.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160991037ebb3f---93604186454.pdf
    • https://jagominum.com/contents//files/88216073706.pdf
    • http://anm-av.de/uploads/files/warefunir.pdf
    • http://svsteinfurth.de/radsportfiles/file/85333824674.pdf
    • http://for-rent-aalst.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607845b17cad5---33788747837.pdf
    • http://zkmeiqi.com/admin/ckfinder/upfile/files/94410152286.pdf
    • https://mikepromedia.com/wp-content/plugins/super-forms/uploads/php/files/tpvraqe969rt3o0kc31epkjmb0/tumajomivugidilaxuwik.pdf
    • http://ophirtonhotel.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1608c865e5bcc0---94174634779.pdf
    • https://www.nrlandscapes.co.uk/wp-content/plugins/super-forms/uploads/php/files/596ac118fb3a4d840447e4b1c379fa86/demozifezu.pdf
    • https://www.frankreich-ferien.ch/wp-content/plugins/formcraft/file-upload/server/content/files/16086f9117d14b---bugowufizeg.pdf
    • http://securitydirect.it/wp-content/plugins/super-forms/uploads/php/files/113b6cd32b3a42053f687eea8ffdc227/losegebajimafezogulebil.pdf
    • https://actorconseil.com/files/file/kipumo.pdf
    • https://www.hungryalex.com/wp-content/plugins/super-forms/uploads/php/files/11566be05f2d6cdb89bb3cca3df97cda/65207717018.pdf
    • https://teenvolunteer.org/wp-content/plugins/super-forms/uploads/php/files/b97df5bc22598c5a1aa835d11c7be60e/wamuxurupaj.pdf
    • http://traiteur-ribot.fr/userfiles/file/salukubixososi.pdf
    • http://challendor.com/fckeditor/upload/file/dojobalukukawenasenog.pdf
    • http://artside.org/data/temp/file/84643462855.pdf
    • https://amesmedicalservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091e51b6e915---91763249765.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/BkSY9tpko7c/uplcv?utm_term=suma+resta+multiplicacion+y+division+de+polinomios+ejercicios+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_off0000fc37.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xFC37 16792 bytes
font_01_sfnt_off00011449.bin
39e468f477987479db42cdc5ae323959d295fb7e92cd0758fd352b0fa7b6439b
pdf-font-stream PDF embedded font (sfnt) at offset 0x11449 17684 bytes
font_02_sfnt_off0001411d.bin
d21165ddc0050a717ab97b26fe6c41e25ec8769e7be73ae05a4bebe439ec6af2
pdf-font-stream PDF embedded font (sfnt) at offset 0x1411D 11264 bytes