Malicious PDF — malware analysis report

Static analysis result for SHA-256 87d4351c32d9234d…

MALICIOUS

PDF

88.7 KB Created: 2021-09-18 19:05:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: aea055a6748dda0ac826a6a88db19ea7 SHA-1: c622cc5e7c2dcdd8fbf158af20ddb1d2b4e6abad SHA-256: 87d4351c32d9234dc478cd8d585077a179aac7579c0a065d40e7a26a22520eb6
156 Risk Score

Malware Insights

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

The PDF contains a large number of embedded URLs, many of which point to websites hosted on compromised CMS platforms or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely related to phishing or SEO manipulation through link farms. No scripts were extracted, and the document body was unreadable, but the URL analysis and heuristic firings are sufficient to assess the attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

Heuristics 6

  • 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 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://cuathepvangohaiduong.com/images/ckeditor/files/14372588941.pdf
    • https://lacgl.org/upload/editor/file/fetaf.pdf
    • http://rajhansnursery.com/userfiles/file/gakufiwufoloruvosogoselop.pdf
    • http://www.offshoreyachts.net/web_upload/editor/files/26342026282.pdf
    • http://dentalcenterstudio.it/userfiles/files/sojezegokegizajodapasa.pdf
    • https://bf-pomosch.ru/wp-content/plugins/super-forms/uploads/php/files/bo035dhrj7sgn8vs4ddubkfsg2/rimewefupogosatafireden.pdf
    • http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613e0e80d62b7---83315394264.pdf
    • https://mhreng.com/userfiles/file/66348887620.pdf
    • https://www.partyshuttlebus.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613a811288ec1---domovodufabebafasovixa.pdf
    • http://auswallendorf.de/userfiles/file/tekolebilarifirujof.pdf
    • http://flemingdecal.com/uploads/assets/file/famasun.pdf
    • https://doellefjelde-mussemarked.dk/images/newsmail/file/76297079792.pdf
    • http://iglozawiercie.pl/zdjecia/file/91192978680.pdf
    • https://www.glasswindowequipment.com/wp-content/plugins/super-forms/uploads/php/files/1581ad322ef2d26f7dc499333ac7a0af/37229154080.pdf
    • https://sayurmateng.com/contents/files/86512314477.pdf
    • https://ethnicminorities.heephong.org/ethnicminorities/cmsadmin/ckfinder/files/29320357401.pdf
    • http://www.risingstars.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/16131d3aaea78f---6360706325.pdf
    • http://ozhelalikram.de/resimler/files/4938636824.pdf
    • http://zbraneklapka.cz/ckfinder/userfiles/files/7314559648.pdf
    • http://isagenixmakessense.com/ckfinder/userfiles/files/vuvizarurabafukawelev.pdf
    • http://freeski.hu/freeski/file/nativawutularifogewinakep.pdf
    • https://shindah.com/images/ckeditor_img/files/sukuri.pdf
    • https://bloomlight.pl/_bloom/file/pigadozebobise.pdf
    • http://zanethompson.com/userfiles/file/47669710049.pdf
    • https://exihomes.com/userfiles/files/tizusitirebalozo.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=sat+question+paper+2018+pdf+download
    • 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_off0000f0bf.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF0BF 16792 bytes
font_01_sfnt_off000108d1.bin
ea4c6095f08e5e2b6390c2f458f004f34dac15f2d0e32ef0581273f9c6cd1115
pdf-font-stream PDF embedded font (sfnt) at offset 0x108D1 18108 bytes
font_02_sfnt_off000137dd.bin
acd481306c546951258c2669d42976237b13b4187e8d7b098a85e6a2c0cd9e3f
pdf-font-stream PDF embedded font (sfnt) at offset 0x137DD 11400 bytes