Malicious PDF — malware analysis report

Static analysis result for SHA-256 a40d1c085b7633da…

MALICIOUS

PDF

81.9 KB Created: 2021-09-01 00:11:32 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-05
MD5: 6e7a362690ca3aae7fedee23f97d5096 SHA-1: 73cd64eec76fcabe20a1562f6eb3f34b61cfffb0 SHA-256: a40d1c085b7633daaafc9525b5909ce46e0c0a4db0e0a0b1233f7069ada93c5f
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm hosted on compromised WordPress sites, with numerous distinct hosts and URLs pointing to PDF files. The presence of multiple compromised CMS upload links suggests an attempt to disguise malicious content within seemingly legitimate infrastructure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9987

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://avantkart.com/wp-content/plugins/super-forms/uploads/php/files/ikldmeq0p0m8ql7t1s4kumjuc1/fosapeda.pdf In PDF document text
    • http://lichnyiybrand.ru/wp-content/plugins/formcraft/file-upload/server/content/files/16078af8064254---56648011739.pdfIn PDF document text
    • http://ciaooo.ru/uploades/userfiles/file/18629712144.pdfIn PDF document text
    • https://ceilford.org/wp-content/plugins/super-forms/uploads/php/files/1b09b19320c4c06cc224a5fe016ede7e/16616249711.pdfIn PDF document text
    • https://weinquartier.at/wp-content/plugins/super-forms/uploads/php/files/86e4127e2b1e5edb756c567d05cad399/59995172433.pdfIn PDF document text
    • http://scro.ru/pic/file/kufedovufotikikopavanaka.pdfIn PDF document text
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/c28dfa04760f918aac9fa8c966827f73/81168202271.pdfIn PDF document text
    • http://www.altrus.pl/wp-content/plugins/formcraft/file-upload/server/content/files/16128ea909ff4a---dowebuberipurivemaxi.pdfIn PDF document text
    • https://quangcaonoithatgiahung.com/admin/webroot/upload/image/files/xelolu.pdfIn PDF document text
    • https://ludifrance.fr/userfiles/file/31452657360.pdfIn PDF document text
    • http://galgalesh.com/userfiles/file/lipusokirugufifivupedika.pdfIn PDF document text
    • http://bibrka-school.org.ua/ckfinder/userfiles/files/3590916412.pdfIn PDF document text
    • http://top1np.com/ckfinder/userfiles/files/tanegor.pdfIn PDF document text
    • https://agribusiness.pk/wp-content/plugins/formcraft/file-upload/server/content/files/16080f2885833d---xutogaruxofinezoz.pdfIn PDF document text
    • http://ordineveterinarivenezia.eu/userfiles/files/fafawudirigejemosujovok.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1607f5d10ba052---bamabekekafif.pdfIn PDF document text
    • https://www.vbclighting.com/wp-content/plugins/super-forms/uploads/php/files/6588f09fff6c763ffd71a824d6e271e8/88312420322.pdfIn PDF document text
    • https://www.financedeclined.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160ac8b3c45eba---zasawumafanu.pdfIn PDF document text
    • http://www.morenoroofing.com/wp-content/plugins/formcraft/file-upload/server/content/files/16083deb3a8864---vetikojifimepivarigat.pdfIn PDF document text
    • https://lifesmart.ro/ckfinder/userfiles/files/botetukaduvano.pdfIn PDF document text
    • https://detskeihriska.eu/ckfinder/userfiles/files/81922887084.pdfIn PDF document text
    • http://mondoacquapiscine.com/userfiles/files/wadazonorinuxelowomeno.pdfIn PDF document text
    • https://bearings.vn/images/ckeditor/files/giwirulelatiropu.pdfIn PDF document text
    • https://inclinedigital.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609204a44139b---xuvebobeki.pdfIn PDF document text
    • https://homeaestheticsllc.com/wp-content/plugins/super-forms/uploads/php/files/97dce5b45fcc5ff805e6ece2808309ee/kewowaxojozomigabu.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/PmAiG5ZyT-k/uplcv?utm_term=parallel+operation+of+transformer+pdfPDF 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_off0000dd4d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD4D 16836 bytes
SHA-256: b232d15a52f8ec015be03c93cec49eeb0828d17df6c72b55f708f48ed8375f0d
font_01_sfnt_off0001090b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1090B 10660 bytes
SHA-256: 18d0abb0b2d9ccbb5e30ad24b19edc948fae47495f6b6309c481e82cd2024ed5
font_02_sfnt_off00012169.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12169 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1