Malicious PDF — malware analysis report

Static analysis result for SHA-256 6820b9a958989a42…

MALICIOUS

PDF

68.3 KB Created: 2021-10-04 09:29:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-24
MD5: 396f7811475e9a6f7591ade3f41d21cc SHA-1: 1c419c20e2100cc52fcc30e4131d04292a6a3db4 SHA-256: 6820b9a958989a42bffdf32dda602529435e9ca394eea6e3a2bb57a017fad446
126 Risk Score

Malware Insights

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

The PDF document was flagged by multiple heuristics, including a critical ClamAV detection and an ML classifier, indicating malicious intent. The presence of numerous embedded URLs, many pointing to disposable domains and forming a link farm, suggests a phishing or redirection scheme. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, further obscuring its true purpose.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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 http://sun-tes.ru/files/file/kukobetopejanorirasikage.pdf In PDF document text
    • http://adice-area.com/pictures/files/31772014010.pdfIn PDF document text
    • http://biurod9.pl/public/userfiles/file/sasoripejef.pdfIn PDF document text
    • http://geoscan.it/userfiles/files/sazelukebozapavud.pdfIn PDF document text
    • http://avtokapriz42.ru/userfiles/file/merejunalibaxagokumoweri.pdfIn PDF document text
    • https://brs.jo/userfiles/files/fasibiwaxovom.pdfIn PDF document text
    • https://steammining.com/userfiles/file/merozejoduvegaxujeninarer.pdfIn PDF document text
    • http://boxerdapolenta.com/cmsimple/images/file/zemeferofururuvepotana.pdfIn PDF document text
    • http://azstorestudio.com/uploads/files/lufebavujabufabemo.pdfIn PDF document text
    • http://uelzecht.lu/userfiles/files/77180676583.pdfIn PDF document text
    • https://educhina.mn/editor/files/31786913720.pdfIn PDF document text
    • https://macjiboter.macjahisa.si/files/file/88054867885.pdfIn PDF document text
    • https://festivaldelmaridaje.com/sgi_userfiles/userfiles/files/wupexavoku.pdfIn PDF document text
    • http://grafichesirio.com/userfiles/files/32815302186.pdfIn PDF document text
    • https://getracemirates.com/userfiles/files/pejififipa.pdfIn PDF document text
    • http://yhbinternational.com/userfiles/file/ratevibekajerebamofege.pdfIn PDF document text
    • https://marthomaktrplrdiocese.org/ckfinder/userfiles/files/6053111639.pdfIn PDF document text
    • http://loaamtran.com/files/usersfiles/files/gofebep.pdfIn PDF document text
    • https://avflash.nl/upload/files/zajufizubuvowopibiwu.pdfIn PDF document text
    • http://www.trimbleexpress.sk/wp-content/plugins/formcraft/file-upload/server/content/files/161452c0b77189---gozidisaduvokesi.pdfIn PDF document text
    • https://safrano.pl/userfiles/file/19027511047.pdfIn PDF document text
    • http://srub-servis.ru/userfiles/file/gimebeferumofuxul.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=pending+felony+chargesPDF 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_off0000abe4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xABE4 15832 bytes
SHA-256: 10b9d2beee3433816d2ef1cb0c46c29ce6f23f72b464e42b628a7ece735b5a7e
font_01_sfnt_off0000d3da.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3DA 10772 bytes
SHA-256: 5aec00f44c5225e998667a3541c771c93611fd351e3b88a7d86298695fed85ca
font_02_sfnt_off0000ec5c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC5C 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1