Malicious PDF — malware analysis report

Static analysis result for SHA-256 f91cd951ea770afb…

MALICIOUS

PDF

87.8 KB Created: 2021-10-17 01:10:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 16b565daec30397f4e091aacac149bc0 SHA-1: 02c9960f3231f08c08869d9b58a2c75c712dc336 SHA-256: f91cd951ea770afbbef096b30a8499be8b70e0174f46304a705019e4876818a0
156 Risk Score

Malware Insights

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

This PDF was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains numerous links pointing to compromised WordPress uploads and other disposable hosting, indicating a link farm designed to redirect users. The presence of external URIs and link farms suggests an attempt to lead users to malicious sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9979

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://himalayanthailand.com/image/upload/File/61517664692.pdf In PDF document text
    • http://lso-msm.com/userfiles/file/nalif.pdfIn PDF document text
    • https://akemi.ro/hirek/file/28252873668.pdfIn PDF document text
    • https://dudikom.pl/userfiles/file/77052303161.pdfIn PDF document text
    • https://www.ibyservice.com/wp-content/plugins/super-forms/uploads/php/files/c2dfa57a69f09cdd1095bb8b2f419ae2/36078556485.pdfIn PDF document text
    • https://maytuixachanquynh.kimtuong.vn/isc/public/files/fckupload/file/letisusufimoxa.pdfIn PDF document text
    • https://xtremefitness.com.au/application/third_party/ckfinder/userfiles/files/wurinasemajeve.pdfIn PDF document text
    • http://mengnuanua.com/app/webroot/files/files/wawemu.pdfIn PDF document text
    • http://tainghe.vn/userfiles/file/91845316329.pdfIn PDF document text
    • http://www.herbertvanderbrugghen.nl/draft/silovefefomoxawegu.pdfIn PDF document text
    • http://agriturismoilnoceto.com/userfiles/files/5286132474.pdfIn PDF document text
    • http://evolutionchonburi.com/userfiles/files/panuzavukepok.pdfIn PDF document text
    • http://westpakusa.com/phpsites/vertical_living/uploads/file/purak.pdfIn PDF document text
    • http://fertilityupdates.com/userfiles/files/vosox.pdfIn PDF document text
    • http://trevelsi.ru/ckfinder/userfiles/files/fozizez.pdfIn PDF document text
    • http://dispensapertutti.com/userfiles/files/55722281890.pdfIn PDF document text
    • http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1613602412d473---pubebasulofiva.pdfIn PDF document text
    • https://vayamcs.com/content_files/files/11407347206.pdfIn PDF document text
    • https://www.bountyvacation.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e478b74a06---pupubasetumujibu.pdfIn PDF document text
    • http://elsekmont.eu/userfiles/file/mekupevorejodobemu.pdfIn PDF document text
    • https://melz-feu.ru/upload/folon.pdfIn PDF document text
    • http://fajni3333.fun4two.pl/uploads/assets/file/lazetimagidodetavonikuke.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Gsjc/~3/5bhJmFgkeCE/uplcv?utm_term=cellular+respiration+and+respirationPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000f21e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF21E 18052 bytes
SHA-256: 5dd21bc3cb8a0e2ae29ed0d92a4947a9d7d9f99bfd925cf30aabec7fa693d2f9
font_01_sfnt_off00012188.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12188 10516 bytes
SHA-256: a7f84c5cfdf47a5ee613ae092dab4642dd1fc399584faec1fc842cc74c79a417
font_02_sfnt_off00013996.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13996 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1