Malicious PDF — malware analysis report

Static analysis result for SHA-256 81a2940f317b6e13…

MALICIOUS

PDF

83.1 KB Created: 2021-09-19 16:04:44 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: c09200f51824c90fd83fa85e35c2d150 SHA-1: 903cab9cee5fd57cf814487d899a77f682b713b8 SHA-256: 81a2940f317b6e13255afb9a814079980d23dcfded60e6397a32b8fb7259a3ad
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains an embedded JavaScript stream and numerous external URIs, many of which point to compromised or disposable hosting. The heuristic 'PDF_SEO_DISPOSABLE_LINK_FARM' indicates the document is designed as a link farm on disposable hosting, likely to distribute malicious content or phish for credentials. The ML classifier and ClamAV detection strongly support its malicious nature.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

Heuristics 7

  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://krisoc.ru/uplcv?utm_term=desktop+live+wallpaper+app+download
    • http://k-ookuma.com/js/upload/files/65259348506.pdf
    • http://www.autoservis-hubatka.cz/admin/upload/ww/file/gawajadewemaforod.pdf
    • https://bibonatura.hu/ckfinder/userfiles/files/pitaboxipipufemi.pdf
    • http://nissanotogovap.net/uploads/images/files/54260326669.pdf
    • http://telegid.tv/userfiles/file/23272922776.pdf
    • https://worldkelo.com/wp-content/plugins/super-forms/uploads/php/files/7412ad163920b17597af2eda0e3a0160/84620020277.pdf
    • https://pastravariaizvoarelebratiei.ro/images/file/3814272522.pdf
    • https://heritran.vn/uploads/news_file/8723925547.pdf
    • https://xtremefitksa.com/ckfinder/userfiles/files/pepimuguvusidapanevej.pdf
    • http://plafondchauffant.fr/img/user/file/68389031251.pdf
    • http://hoilhpnqbthanh.com/upload/file/96791120617.pdf
    • http://mikomisushi.com/uploads/files/8378329903.pdf
    • http://begemot-rus.com/uploadfiles/file/2021090408010673499.pdf
    • https://globalmediaminds.com/uploads/files/xemerusakebodavenamevixum.pdf
    • http://centromedicoveterinarioadda.com/userfiles/files/dinumu.pdf
    • http://aczelzalog.hu/tmp/jabosusojafakukorigeginuf.pdf
    • https://clickbox.ro/images/file/koposawomozurob.pdf
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/161357c250de73---36739648984.pdf
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1613820fb527ff---62254248770.pdf
    • http://www.sindafaz.com.br/admin/editor/ckfinder/userfiles/files/50818329728.pdf
    • http://cnwt.mgo.cool/upfile/files/2021/09/17/zagofolaxawuwivijogugir.pdf
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/16135211d17991---jaxuvej.pdf
    • http://stavclearing.ru/upload/files/25034308920.pdf
    • https://get-insurance.in/ckfinder/userfiles/files/31065347705.pdf
    • http://recko.ru/ckfinder/userfiles/files/85291585482.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_off0000dff1.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xDFF1 16792 bytes
font_01_sfnt_off0000f803.bin
b3d0acd6440b31fe88fa8e115b6e448cca3042b66ec7cb5e78bd1849539a39c5
pdf-font-stream PDF embedded font (sfnt) at offset 0xF803 17576 bytes
font_02_sfnt_off000125eb.bin
fce963431509770ab99c85a881636170c208530df04921ef188af8b92a6f15d4
pdf-font-stream PDF embedded font (sfnt) at offset 0x125EB 10628 bytes