Malicious PDF — malware analysis report

Static analysis result for SHA-256 3ffbbc6037b1c045…

MALICIOUS

PDF

69.6 KB Created: 2021-09-20 19:19:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: e650620f47d3b2448e6a6f23481ffad8 SHA-1: 25262cd6276031ee942493c458128e073dcbc12b SHA-256: 3ffbbc6037b1c045b2dcbc7cf5e1eb3d318c94f284700d2f27fce47532525e93
164 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains embedded JavaScript, which is a common technique for executing malicious code. Several heuristics indicate the PDF is part of a link farm, with many external URIs pointing to potentially compromised or disposable hosting. The ClamAV detection and ML classifier strongly suggest malicious intent, likely to download and execute a second-stage payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

Heuristics 7

  • 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.
  • 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 http://arcstema.com/userfiles/files/62233909726.pdf In PDF document text
    • https://ceccarmaramures.ro/userfiles/file/vobugikidubolib.pdfIn PDF document text
    • http://centralcogtc.com/uploads/file/33949221306.pdfIn PDF document text
    • https://optical-axis.com/uploads/files/202109200318553579.pdfIn PDF document text
    • https://nmcs.ca/userfiles/files/zexoxovoxegumufoxalimel.pdfIn PDF document text
    • https://infotechb2blite.com/bot/ckfinder/uf/files/samajaluzer.pdfIn PDF document text
    • https://enville.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613e9637e5d3d---94972036471.pdfIn PDF document text
    • http://xperion.hu/wp-content/plugins/super-forms/uploads/php/files/d16e51ef70058d5e7cd5fb8be7b9638b/94556450787.pdfIn PDF document text
    • http://anhuishangbiao.com/upload_fck/file/2021-9-3/20210903044725237008.pdfIn PDF document text
    • http://vpsystem.com/files/fck/loduwerajedukusudubumix.pdfIn PDF document text
    • http://www.ernakulamarchdiocese.org/www/js/ckfinder/userfiles/files/ladobosodokatezivum.pdfIn PDF document text
    • http://lucchetta.net/userfiles/files/jaratumerew.pdfIn PDF document text
    • http://sotel-perm.ru/site/file/45919851321.pdfIn PDF document text
    • http://sns.hu/_user/file/kavusapu.pdfIn PDF document text
    • http://espokebar.com/uploads/files/garasabasogi.pdfIn PDF document text
    • http://xiangzhuan.tw/upload/files/fiwunerimivizuvaxomunaw.pdfIn PDF document text
    • https://tierrettung-in-katalonien.org/ckfinder/userfiles/files/gedot.pdfIn PDF document text
    • http://hftyby.com/upload_fck/file/2021-9-20/20210920014640338919.pdfIn PDF document text
    • https://mandarinusa.com/userfiles/file/1632029199.pdfIn PDF document text
    • https://www.sacproblemleri.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c801c7d975---sekufakaxizopisebuletez.pdfIn PDF document text
    • http://www.creativitaecomunicazione.it/js/lib/ckfinder/userfiles/files/vokunut.pdfIn PDF document text
    • http://citra.cl/userfiles/file/96503535652.pdfIn PDF document text
    • http://www.stadion-zarya.ru/ckfinder/userfiles/files/nibadefogogowivatur.pdfIn PDF document text
    • https://vasantviharproperties.com/userfiles/file/fumimiva.pdfIn PDF document text
    • http://hunting.kg/userfiles/file/suwuvomunolovineruxaje.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=dns+test+androidPDF 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_off0000b326.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB326 15384 bytes
SHA-256: ff70adaf949e2f6a204408fde9b2b46f3b272d4bef903254b24eb59e33307188
font_01_sfnt_off0000d9c9.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD9C9 10196 bytes
SHA-256: a22f1e83108930f395979af11a28c1539f3c7e0b4435605838f248d722e76029
font_02_sfnt_off0000f0c4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF0C4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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