Malicious PDF — malware analysis report

Static analysis result for SHA-256 4ab8a4c23db4042c…

MALICIOUS

PDF

73.3 KB Created: 2021-09-19 00:50:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: bb60651a9acd35504a71f4dca82cbc2f SHA-1: 7178f411f7cf6b73e8e1bf325c3ee58710a8bea5 SHA-256: 4ab8a4c23db4042cc77569b73036caa273a2210ae5c3cb2e300968da96d928bc
156 Risk Score

Malware Insights

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

The PDF file was flagged by ML classifiers and ClamAV as malicious, specifically as a phishing trojan. It contains numerous external links, many pointing to compromised WordPress sites or disposable hosting domains, suggesting a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure but serving as a container for the malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9951

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://laborke.ru/uplcv?utm_term=seven+letter+word+beginning+with+m PDF link annotation
    • https://vaitinhdien.com/app/webroot/upload/files/41151356832.pdfIn PDF document text
    • http://charolais-hessen.de/write/userfiles/file/sopusiguwabobuvov.pdfIn PDF document text
    • http://kaplanpm.com/wp-content/plugins/formcraft/file-upload/server/content/files/161465dcbde41c---47938009323.pdfIn PDF document text
    • http://nuyewpilot.academy/wp-content/plugins/super-forms/uploads/php/files/aeaa79a50c6c8cd22b3045878846d889/zefalijejoxumegi.pdfIn PDF document text
    • http://apnm.indexint.net/ckfinder/userfiles/files/juforosunewixitotesisax.pdfIn PDF document text
    • https://bestmiamiturf.com/wp-content/plugins/super-forms/uploads/php/files/6af85e03777834d81ea6b94d7e96fd88/59773858675.pdfIn PDF document text
    • https://angkalaris.com/contents/files/jorogelutoje.pdfIn PDF document text
    • http://satit.nrru.ac.th/satit/_Adminis/ckfinder/userfiles/files/relozagivibeve.pdfIn PDF document text
    • http://bodemveenweiden.nl/bodem-veenweiden-img/46245579400.pdfIn PDF document text
    • https://alley.52886.tw/uploads/files/mekutinilemijafufipibok.pdfIn PDF document text
    • http://stefanourso.com/public/userfiles/file/sotarusegejotom.pdfIn PDF document text
    • http://www.ddd-iasi.ro/wp-content/plugins/formcraft/file-upload/server/content/files/16143a3ebadf2d---96594871950.pdfIn PDF document text
    • http://familiegravesen.dk/ckfinder/userfiles/files/gusepo.pdfIn PDF document text
    • https://art-gallery.mn/uploads/files/doxopidokoberulewis.pdfIn PDF document text
    • http://trust-law-firm.com/userfiles/file/20210911133141_1505569968.pdfIn PDF document text
    • http://www.fan-consultants.com.tw/ezadmin/ckfinder/userfiles/files/26607275055.pdfIn PDF document text
    • https://negaratoto.com/contents/files/rexamatinonuf.pdfIn PDF document text
    • https://dienhoanghean.com/upload/ck/files/97819245528.pdfIn PDF document text
    • https://unifor975.ca/userfiles/file/6298252231.pdfIn PDF document text
    • http://badischer-kunstverein.de/ckfinder/userfiles/files/rorelolefuw.pdfIn PDF document text
    • http://finadev-groupe.com/userfiles/file/34300942411.pdfIn PDF document text
    • https://sdyh.gr/wp-content/plugins/super-forms/uploads/php/files/din65k0s4l1hna1vgda28dco63/guviz.pdfIn PDF document text
    • http://matras-devison.ru/upload/file/zuwawe.pdfIn PDF document text
    • https://theurbanthinktank.com/files/degigibilixes.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_off0000ba13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xBA13 17272 bytes
SHA-256: f2afaaf2a0ddf1a48224510f592d063f91ef07368b8d762c4e27c53d986ec76e
font_01_sfnt_off0000e75a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE75A 10732 bytes
SHA-256: 1ed9cc6355cf5b1f6adb2525f587958ce9aca456845b3e3de5546576ebcd7f8a
font_02_sfnt_off0000ffa4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFFA4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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