Malicious PDF — malware analysis report

Static analysis result for SHA-256 528c2c4e4d2801f1…

MALICIOUS

PDF

85.3 KB Created: 2021-09-21 19:08:43 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: b18a985e2afdade78d8458c5e6252908 SHA-1: 24722be02eff3cbf39d2119711e9570a2fd2ba4f SHA-256: 528c2c4e4d2801f1d8e4ee31b9e1e6b627616c9ace4f21fbad824f5325b1c083
156 Risk Score

Malware Insights

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

This PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. It contains a link farm with numerous URLs pointing to compromised or disposable domains, likely intended to redirect users to malicious content. The PDF structure itself appears to be a link farm, as indicated by multiple heuristics.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

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://biocenfis.es/uploads/assets/file/92037463288.pdf
    • https://812423.qqtogeljackpot2.com/contents/files/jorudezarumimelogodujitu.pdf
    • http://szpitalstrzelin.pl/userfiles/files/gerul.pdf
    • http://d2dgroup.net/upload/files/86862884081.pdf
    • http://www.restorationservice.ca/wp-content/plugins/formcraft/file-upload/server/content/files/161354b51ee9c3---robasijidibod.pdf
    • https://member-amz-seller-system.de/wp-content/plugins/super-forms/uploads/php/files/4aa06ba03fe70d27f27ca8e7e13857c9/tenovewuzubokalaxaw.pdf
    • https://beta.nhatthiengroup.com/files/uploaded/files/63296604386.pdf
    • http://abwingssuffolk1.com/uploads/files/5791282094.pdf
    • https://alariel.be/userfiles/file/xireluxosagovoxi.pdf
    • http://101-games.ru/images/uploads/files/19515866782.pdf
    • https://xuantruongtech.com/images/ckeditor/files/lozad.pdf
    • https://viettrungson.com/media/Files/5346026199.pdf
    • https://leeleather.net/userfiles/file/404946703.pdf
    • http://stjconsulting.it/userfiles/files/lawidurebulamegas.pdf
    • http://olympusflights.com/files/files/4221551690.pdf
    • http://romengo.com/ckfinder/userfiles/files/98367972006.pdf
    • http://ldkxzzs.com/images/userfiles/file/musoxog.pdf
    • https://didaktika.drmix.cz/uploads/files/sofuta.pdf
    • http://td-mg.ru/uploads/files/luvufewab.pdf
    • http://abwjefferson.com/uploads/files/kazavolidokijokavu.pdf
    • https://doellefjelde-mussemarked.dk/images/newsmail/file/79976522143.pdf
    • https://clinicamanila.com/ckfinder/userfiles/files/2549438268.pdf
    • http://matrixuniverzum.eu/wp-content/plugins/formcraft/file-upload/server/content/files/1613fcb53ce422---21875109375.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/Om9ozkHLxGw/uplcv?utm_term=multiplayer+sex+games+for+android
    • 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_off0000eaf0.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xEAF0 16792 bytes
font_01_sfnt_off00010302.bin
75deb8c9d85d7a502fe2b5a2bda4deefb008286e326e028ab5fa20535d5a1f16
pdf-font-stream PDF embedded font (sfnt) at offset 0x10302 16664 bytes
font_02_sfnt_off00012dfe.bin
a372a3fbd7d7081659158adf197b0b7b33e1770d27c8867799ee1776685a8832
pdf-font-stream PDF embedded font (sfnt) at offset 0x12DFE 11152 bytes