Malicious PDF — malware analysis report

Static analysis result for SHA-256 c52bac3a92ab314b…

MALICIOUS

PDF

77.3 KB Created: 2021-09-17 18:01:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 7a9552791ba8ed5f93c74b674ecd564f SHA-1: a151239a204380103355012b2b5b7344d6b3ef71 SHA-256: c52bac3a92ab314b485e91f045e40aa69997a64e48b58b43f85dbce2a6df5d52
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous external URLs, many pointing to compromised or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely for phishing or distributing further malware. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the heuristic findings.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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://teaterskolen-efteruddannelsen.dk/ckfinder/userfiles/files/mesewo.pdf In PDF document text
    • https://ciiinnovationsummit.com/ci/userfiles/files/1178460871.pdfIn PDF document text
    • http://sage-chem.com/image/files/20210907_113716.pdfIn PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1613c7fbb7c937---4207916114.pdfIn PDF document text
    • https://zebcom.in/userfiles/file/ponakafapa.pdfIn PDF document text
    • http://onlinetalk.jp/app/webroot/img/fckfiles/file/somosipepowekim.pdfIn PDF document text
    • http://sicompk.com/survey/userfiles/files/dasanelipejenela.pdfIn PDF document text
    • http://studiopiergentili.it/userfiles/files/fubewa.pdfIn PDF document text
    • http://dongsimkindergarten.com/upload/files/57565151825.pdfIn PDF document text
    • http://losmarinoslanzarote.com/marinarubicon/admin/file/71124690492.pdfIn PDF document text
    • http://indcms.testingmachines.com/images/file/pozika.pdfIn PDF document text
    • http://studioriboldi.eu/userfiles/files/pojipubogewuwutoxijum.pdfIn PDF document text
    • https://www.andimoda.com/wp-content/plugins/super-forms/uploads/php/files/951b4bbe9dbe1f6a3ca45dcbdfbd7cff/78801708547.pdfIn PDF document text
    • https://doluhosting.com/calisma2/files/uploads/wijovototajazowoninukuna.pdfIn PDF document text
    • http://barcabianca.eu/upload/file/xevutujexatoluguda.pdfIn PDF document text
    • https://tch.lu/files/files/tasagowadoxuvotiwejemoli.pdfIn PDF document text
    • http://meimagedance.tw/ufiles/files/soduzubosetifamevagobo.pdfIn PDF document text
    • http://sanfrancescovet.com/userfiles/files/muguruvixapuj.pdfIn PDF document text
    • http://smartmedicaleg.com/wp-content/plugins/formcraft/file-upload/server/content/files/161428b8f08abe---wavaleturugexuvazo.pdfIn PDF document text
    • http://krakowska98.com/zdjecia/fck/file/64984252435.pdfIn PDF document text
    • https://saftanton.dk/wp-content/plugins/formcraft/file-upload/server/content/files/1613ffb0428f89---xajopofuxoro.pdfIn PDF document text
    • http://nitecoreromania.ro/files/file/69643991719.pdfIn PDF document text
    • https://praktijk.zorglink.nl/ckfinder/userfiles/files/gesovipovirumitosugin.pdfIn PDF document text
    • http://www.pethouse.es/ckfinder/userfiles/files/siveduv.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/YTWXjIUwRh0/uplcv?utm_term=using+wifi+and+hotspot+at+the+same+timePDF 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_off0000c8cb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC8CB 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e0dd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE0DD 17724 bytes
SHA-256: bfe66bd6b24d2421a5049d5f2f1f4c2319038ab76080b7032550074cba5b930c
font_02_sfnt_off00010edc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10EDC 10892 bytes
SHA-256: b1c878f2df4e5024b5fdb2b19939fd651f57e2b9aa6e6572b2b08dadd6dc4146