Malicious PDF — malware analysis report

Static analysis result for SHA-256 a4ff8bafb80c5893…

MALICIOUS

PDF

95.0 KB Created: 2021-09-12 10:32:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: f582daecc1d0ffb280ff0289928f8c0a SHA-1: d9ea3e0d00d11891c0ed797b4c71643ded01e6db SHA-256: a4ff8bafb80c58936f7308cdda6459401f56f872d26e4e2ddeb23171ed3fe818
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and a machine learning classifier indicated a high probability of maliciousness. Heuristics indicate the document functions as a link farm, directing users to multiple compromised or disposable hosting sites, including one associated with a compromised WordPress upload. The presence of external URIs and link farm characteristics suggests an attempt to redirect users to malicious content, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9888

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://smidgel.ru/uplcv?utm_term=minecraft+beta+ios PDF link annotation
    • http://andreuma.madteam.net/ckfinder/userfiles/files/kaladiximu.pdfIn PDF document text
    • https://learn-atdi.com/uploads/files/4387174331.pdfIn PDF document text
    • http://abakus-routing.co.uk/ckfinder/userfiles/files/toxunasetetago.pdfIn PDF document text
    • http://tnslib.net/userfiles/files/juzesipunezixumavapaxiz.pdfIn PDF document text
    • http://ccswcd.com/userfiles/file/vupese.pdfIn PDF document text
    • http://nataliashishkina.com/userfiles/file/89419939277.pdfIn PDF document text
    • http://ominocoibaffi.it/userfiles/files/modapefaxigevoterotubetus.pdfIn PDF document text
    • http://2015.letnifestiwal.pl/ckfinder/userfiles/files/sapukipivilagezi.pdfIn PDF document text
    • http://minisadik-margaritka.ru/admin/ckfinder/userfiles/files/mukatagozilikupolimufure.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/4e3c705cdb1795ee0a0997fc450b3410/repemelagubil.pdfIn PDF document text
    • https://webmedcentralplus.com/userfiles/file/34889210703.pdfIn PDF document text
    • https://negaratoto.com/contents/files/28219897282.pdfIn PDF document text
    • http://artgrafika.cz/userfiles/file/80098919118.pdfIn PDF document text
    • http://kantoromega.pl/userfiles/file/7764971442.pdfIn PDF document text
    • https://holycrosshealthcare.com/userfiles/files/81374011702.pdfIn PDF document text
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/161358fa8b3f72---xokirufebopix.pdfIn PDF document text
    • https://ilexgold.com/app/webroot/files/userfiles/files/lakeguzasapipubasoxubana.pdfIn PDF document text
    • http://nkmate.com/FileData/ckfinder/files/20210905_054A26F847B36CB6.pdfIn PDF document text
    • https://hmanagement.net/userfiles/file/40991809946.pdfIn PDF document text
    • http://studiotravenzolo.it/userfiles/files/nudimixajugo.pdfIn PDF document text
    • https://stdtekstil.com/upload/ckfinder/files/59020184718.pdfIn PDF document text
    • https://j26clean.com/upload/files/kekukolusamubatobi.pdfIn PDF document text
    • http://jca-t.com/fck_image/file/solanitomasajesi.pdfIn PDF document text
    • https://www.advids.co/wp-content/plugins/formcraft/file-upload/server/content/files/1612f8c4b482f3---pemomanokesobizupujuri.pdfIn PDF document text
    • http://stevis.cz/files/file/39168421020.pdfIn PDF document text
    • http://nhanvietgroup.com/demo/xay-dung-tnx/upload/files/60771069113.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_off00010b1a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10B1A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012331.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12331 10416 bytes
SHA-256: 5879db2301a68d06e3dce1746128dd6dbe7861e71fe14f328dddd4b722c50534
font_02_sfnt_off00013af3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13AF3 19684 bytes
SHA-256: 55c3ec4bb562a1acfee339c05b2b9899961dcf717c66e944046aedfb78f9d70b