Malicious PDF — malware analysis report

Static analysis result for SHA-256 83553103eae917e1…

MALICIOUS

PDF

73.3 KB Created: 2021-06-22 21:20:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7)
MD5: 0051056e7f284d46e57c0561b7205442 SHA-1: 7e94db1a9c71ac954beabd327bcdf9a35b53e1df SHA-256: 83553103eae917e171d8b737b831c253e20fdb73c8ae337daf207842f09852db
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1059.007 JavaScript

The sample is identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. It contains numerous links to external websites, many hosted on compromised WordPress installations, suggesting a phishing or malware distribution campaign. The document body, though heavily obfuscated, contains references to 'medical certificate handwritten' and 'wkhtmltopdf', indicating a lure to disguise malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9998

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://oniceh.ru/uplcv?utm_term=medical+certificate+handwritten
    • http://bigxra.com/uploadfile/file/2021062101083573499.pdf
    • http://protech.com.ng/wp-content/plugins/formcraft/file-upload/server/content/files/160b4deebcae52---xudupijot.pdf
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e2613dff49---rasidiweli.pdf
    • http://www.jhannahs.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c8dcfe85adf---52592143536.pdf
    • http://hattrick-sports.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a72ac53caaf---jirufuloma.pdf
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160845c99f0b1d---rufijivaxi.pdf
    • http://msiutilities.biz/documents/dofizapusesupofoxukuvav.pdf
    • https://socialacademy.gr/wp-content/plugins/super-forms/uploads/php/files/872b626ae10d8bb2e0956286ebb213cd/fidoduxo.pdf
    • https://www.lumisolar.pe/wp-content/plugins/formcraft/file-upload/server/content/files/160b846ca9cc3e---fuwafudujovozotodojoruto.pdf
    • https://www.energetisch-therapeut-estie.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16085827109685---bugujeziwa.pdf
    • https://mls.lighting/wp-content/plugins/super-forms/uploads/php/files/5d47b325b5c5103250fb83b8ba9dc19b/96968812280.pdf
    • http://www.norestim.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16085748219e6f---mojovanukilirusuzixedoxax.pdf
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/f448b4c4f19c2d45e1431130bf4a41be/95895568.pdf
    • http://ljhalls.com/wp-content/plugins/super-forms/uploads/php/files/fa51d5cffe0bbfdfd2857255c8418779/65297553142.pdf
    • http://www.timtransportes.com/home/wp-content/plugins/formcraft/file-upload/server/content/files/160a4b5380a4a4---7202039541.pdf
    • http://meteosputnik.ru/userfiles/file/66319870449.pdf
    • http://www.ascendercorp.com/
    • http://www.ascendercorp.com/typedesigners.html
    • 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://scripts.sil.org/OFL

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000e228.bin
bdde9dafc9cd38c4b0334314cd58bb2f0adf223e16c99e1095777b00bf4e8499		 pdf-font-stream PDF embedded font (sfnt) at offset 0xE228 5028 bytes
font_01_sfnt_off0000f359.bin
c37767c83b66d87f510e4b0f662de698a74ffb3763cbd6fd19aae229524bf714		 pdf-font-stream PDF embedded font (sfnt) at offset 0xF359 10772 bytes

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