Malicious PDF — malware analysis report

Static analysis result for SHA-256 838ebdd1480c5159…

MALICIOUS

PDF

88.1 KB Created: 2021-09-15 00:08:26 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: 81a33db5e1759c5872df580949f6d650 SHA-1: 7fff6ed837a5580eb3d73f63aedae6889ac997a9 SHA-256: 838ebdd1480c51597c8cd5b355319a948a44fcfa72b5ea6795e0d1758eb19701
134 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. The presence of embedded JavaScript and numerous external URIs, many hosted on disposable domains, suggests the document is designed to redirect users to malicious sites. The `PDF_SEO_DISPOSABLE_LINK_FARM` heuristic further supports this, indicating a tactic to obscure the true malicious destination.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9988

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
  • 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.
  • Embedded JS stream low PDF_JS
    PDF references a /JS stream. Generic JavaScript is common in benign forms; specific dangerous APIs are scored by separate rules.
  • 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://allytemp.ru/uplcv?utm_term=windows+10+grub+not+showing PDF link annotation
    • http://phayaotechno.com/UserFiles/File/61300707270.pdfIn PDF document text
    • http://www.performhabitat.fr/bundles/astadmin/js/ckfinder/userfiles/files/10781031924.pdfIn PDF document text
    • https://thebottombillion.org/business_school/uploads/file/nuxededulosa.pdfIn PDF document text
    • http://vizcsap.hu/files/file/86758497996.pdfIn PDF document text
    • https://bauarch.bg/files/92445794788.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/16133bed4bba17---sotubifuparigaboren.pdfIn PDF document text
    • https://infravoip.com/wp-content/plugins/super-forms/uploads/php/files/08a249d7994e76e7c578ef39195482be/wutubezuwotobupexe.pdfIn PDF document text
    • https://gencatakan.com/upload/file/punesuwobubuwafini.pdfIn PDF document text
    • http://albertf.madteam.net/ckfinder/userfiles/files/2491640329.pdfIn PDF document text
    • http://xn----7sbjvweekof5d.xn--p1ai/files/files/31569914388.pdfIn PDF document text
    • https://zapret-rf.org/web/img/podborky/files/78594062939.pdfIn PDF document text
    • http://mardeestilos.es/fotos/file/59858869069.pdfIn PDF document text
    • http://clairerolo.com/userfiles/file/83240409300.pdfIn PDF document text
    • http://dabaizhongxue.com/upload_fck/file/2021-9-6/20210906135627341419.pdfIn PDF document text
    • https://asi-filter.pl/files/file/tebuk.pdfIn PDF document text
    • https://www.bakkersvlaanderen.be/resources/plugins/ckfinder/userfiles/0/files/31468684346.pdfIn PDF document text
    • http://sivam.pl/files/file/38604115780.pdfIn PDF document text
    • https://edenestates.com/ckfinder/userfiles/files/7306362692.pdfIn PDF document text
    • https://eastmanllc.com/ckfinder/userfiles/files/bagewi.pdfIn PDF document text
    • http://xn--h1agcmh.com/ckfinder/userfiles/files/6629177908.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_off0000f459.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF459 10680 bytes
SHA-256: 8abf983e015e8958f8179f2cbe28100e47adc41c3721f31792e30e5e288b4011
font_01_sfnt_off00010c97.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C97 17744 bytes
SHA-256: 57741eef57938ab218efe9c9017ec4da1f4f90fbf02ce33ff16da472b2c1fea5
font_02_sfnt_off00013b08.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13B08 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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