Malicious PDF — malware analysis report

Static analysis result for SHA-256 e4a93f4c79710c09…

MALICIOUS

PDF

73.6 KB Created: 2021-10-03 18:33:25 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-31
MD5: 765a784233718a00b32599eb6f8f7541 SHA-1: aff058aec5c3b5dcccfeaef4cca718e24a7edc25 SHA-256: e4a93f4c79710c09b79de4ac06e41cd7fb64cf3763d5d16f6db80edb49fba789
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It contains numerous embedded URLs, many of which point to compromised or disposable domains, suggesting a link farm designed to redirect users to malicious sites. The 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' heuristics further support this, indicating a tactic to obscure the true destination of the links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9939

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 https://stephankeppel.com/userfiles/file/kulirokigazetasiput.pdf In PDF document text
    • https://i-intelli.com/ckfinder/userfiles/files/24762383704.pdfIn PDF document text
    • http://inistor.com/ufiles/files/bemelufevilukibit.pdfIn PDF document text
    • http://multi-accueil.fr/ressource/site-image/files/zotasojewa.pdfIn PDF document text
    • http://uniondeautoescuelas.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ac25da7d69---56594235427.pdfIn PDF document text
    • https://www.cfo-search.com/wp-content/plugins/formcraft/file-upload/server/content/files/16153b2b7e9f44---22053181996.pdfIn PDF document text
    • http://ocean-ex.com/images/blog/file/sobuto.pdfIn PDF document text
    • https://blsautomation.com/ckfinder/userfiles/files/vozuvelunitesow.pdfIn PDF document text
    • https://promise-land.com/upload/file/43182776710.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/16410ab1911afbce00f077aa804bb65d/vanepapexajawu.pdfIn PDF document text
    • https://people11people.gr/uploads/File/sivevexawanapomus.pdfIn PDF document text
    • http://hide-bo.com/img/tmp/file/30300325197.pdfIn PDF document text
    • http://ammk.sk/userfiles/file/wisub.pdfIn PDF document text
    • http://kesherisrael.com/uploadEditor/files/7927768861.pdfIn PDF document text
    • http://star-transform-moscow.ru/uimg/files/junojub.pdfIn PDF document text
    • http://nhatngungoisaoxanh.com/upload/files/50729688675.pdfIn PDF document text
    • http://xn--e1aazeoc7d.xn--p1ai/images/shared/file/51827963881.pdfIn PDF document text
    • https://badeluxe.com/userfiles/files/48287619660.pdfIn PDF document text
    • https://cupanghitam.com/contents/files/vitiponusi.pdfIn PDF document text
    • https://fajndoktor.cz/images/file/files/zokizaduwadud.pdfIn PDF document text
    • https://mttrasportisrl.it/dati/upload/file/37903895221.pdfIn PDF document text
    • http://chemicalengineers.ie/images/80120656330.pdfIn PDF document text
    • https://karthikaspices.com/uploads/file/jopefejiligegobedojo.pdfIn PDF document text
    • https://bczenekar.hu/files/file/44468940458.pdfIn PDF document text
    • http://satakantaresort.com/user_img/files/lokudugilidumas.pdfIn PDF document text
    • http://av-jet.ru/userfiles/file/97275131867.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/YTWXjIUwRh0/uplcv?utm_term=kinetic+energy+in+rotational+motionPDF 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_off0000b8f6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB8F6 18624 bytes
SHA-256: 3b51fd4b6a0423a35fd9be4605efc046bf40cf0b034bdbf0902545e74e025e39
font_01_sfnt_off0000e894.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE894 10508 bytes
SHA-256: 683718e4f0d6a950cd9263b19b02179ab1007c1b8466dc038d25ac57c732ca53
font_02_sfnt_off0001007e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1007E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1