Malicious PDF — malware analysis report

Static analysis result for SHA-256 31b4c39f904f11bd…

MALICIOUS

PDF

68.5 KB Created: 2021-10-02 22:50:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 37e0725bbbf5b0b1d1f81affbffe59f6 SHA-1: 36a06008e0c8a2554e6919264781eb38d3a1d9b9 SHA-256: 31b4c39f904f11bdc77d390a0bd41dcb43f5759caeb08b8227f88eb460accf4c
156 Risk Score

Malware Insights

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

The file was detected by ClamAV as Pdf.Phishing.Trojan and flagged by an ML classifier, indicating malicious intent. It contains numerous external URIs and link farm patterns, suggesting it is designed to redirect users to potentially malicious websites. The PDF structure and embedded URLs are consistent with phishing or malware distribution campaigns.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://inwebjor.ru/uplcv?utm_term=very+high+wbc+count PDF link annotation
    • http://whatifitspossible.com/ckfinder/userfiles/files/mikeno.pdfIn PDF document text
    • http://belv.ru/userfiles/file/62709069272.pdfIn PDF document text
    • http://unibox.lv/files/text/vemilitugowuxax.pdfIn PDF document text
    • http://hondatayho.vn/images/ckeditor/files/85649229259.pdfIn PDF document text
    • https://menu2uplus.com/images/file/97574040469.pdfIn PDF document text
    • https://lbk-ingatlan.hu/uploads/file/52894313898.pdfIn PDF document text
    • https://amagi.la/wp-content/plugins/formcraft/file-upload/server/content/files/1613db0137adff---42158884541.pdfIn PDF document text
    • https://gastrotest.co/ckfinder/userfiles/files/59590069389.pdfIn PDF document text
    • http://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/161376eae7c76b---67829391382.pdfIn PDF document text
    • http://banquat.com/userfiles/files/30361840673.pdfIn PDF document text
    • http://www.medical-psychology.gr/wp-content/plugins/formcraft/file-upload/server/content/files/161447bc564721---bepudexef.pdfIn PDF document text
    • http://herium.net/FileData/ckfinder/files/20210912_5B03955B54204755.pdfIn PDF document text
    • http://boek.se/bilder_umeny/File/82075988061.pdfIn PDF document text
    • http://cinstech-inspect-survey.com/fckeditor_userfiles/file/jovapobekisi.pdfIn PDF document text
    • https://clickbox.ro/images/file/92211568268.pdfIn PDF document text
    • http://velocimapper.com/webfiles/file/12212017590.pdfIn PDF document text
    • http://vanprodukt.cz/UserFiles/File/sepujujemafuseke.pdfIn PDF document text
    • http://zpb-maciejewski.pl/upload/fck/file/vusaz.pdfIn PDF document text
    • http://sonhanint.com/uploadpic/sun/files/202109081147347453.pdfIn PDF document text
    • http://nissanotogovap.vn/uploads/images/files/geletusutobonikepaju.pdfIn PDF document text
    • http://oppedisanorobertosrl.com/userfiles/files/molagudupewozufagiwusuga.pdfIn PDF document text
    • https://elemental-ia.com/userfiles/file/61094482338.pdfIn PDF document text
    • http://positiveforce.in/uploads/files/6429756661.pdfIn PDF document text
    • 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_off0000ae44.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xAE44 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000c656.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC656 15244 bytes
SHA-256: b92f2b98726b04c02cf2c7fc1443cdea1afb87c15b6dbf71e96033a9c3a845ab
font_02_sfnt_off0000eced.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECED 10544 bytes
SHA-256: 0a35210c7f9eb1745ab9d4fb4241a8d087e0fb8606ea76562c2661a40034bb5d