Malicious PDF — malware analysis report

Static analysis result for SHA-256 53fcc798ea7c139e…

MALICIOUS

PDF

72.6 KB Created: 2021-09-03 14:00:36 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 92435bc9b575fce1b3dd06850b2b2c72 SHA-1: 70eb9af00107550f6d6a6b82d94215e9f250d323 SHA-256: 53fcc798ea7c139ec459b73d46f61274b67da90969d98f398d8064a4d99f5515
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it's a link farm. The PDF contains numerous external URIs, many hosted on compromised WordPress sites, suggesting an attempt to distribute malicious content or manipulate search engine results. The presence of external links and the nature of the heuristics point towards a phishing or SEO spam attack.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9956

Heuristics 6

  • 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.
  • 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://nomylo.ru/uplcv?utm_term=pharmacology+mcq+pdf+with+answers PDF link annotation
    • https://www.truesdalepainting.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fb77c93f75d---14110673994.pdfIn PDF document text
    • http://perles-del-beya.com/userfiles/file/rokononafi.pdfIn PDF document text
    • https://path.mn/userfiles/files/poreposaguma.pdfIn PDF document text
    • https://www.zulilighting.com/wp-content/plugins/super-forms/uploads/php/files/4a5b1783e2d46b35e859ea86d09e668d/55219349729.pdfIn PDF document text
    • https://baconbites.com/wp-content/plugins/super-forms/uploads/php/files/4pljs0rond9f8r5iv4k3op7g73/83436002398.pdfIn PDF document text
    • http://thebrownbag.vn/upload/files/5330423497.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/16088f32322a4d---zowoteg.pdfIn PDF document text
    • https://amartzon.store/wp-content/plugins/super-forms/uploads/php/files/9a481ae5d5dcc700b71db270e40fab4f/76063188297.pdfIn PDF document text
    • https://cottingham-group.com/cufiles/files/takuzowavelujonos.pdfIn PDF document text
    • http://saktigroup.in/uploads/gasepo.pdfIn PDF document text
    • http://logopeda-empatia.pl/content/file/jolur.pdfIn PDF document text
    • http://namngonviet.vn/user-/files/23506552754.pdfIn PDF document text
    • https://antoinepanau.com/wp-content/plugins/super-forms/uploads/php/files/cfd3d6d76a9885bd5f927e0116cf3c59/lizenidosorotavidaxiz.pdfIn PDF document text
    • https://alnahamgroup.com/userfiles/file/mofebefifaridowaxagoka.pdfIn PDF document text
    • https://radiosmile.hu/upload/file/70423621146.pdfIn PDF document text
    • https://www.blackandwhite-salon.com/wp-content/plugins/super-forms/uploads/php/files/f127c136471cb019439320efdb5dee67/nikujinakutemo.pdfIn PDF document text
    • http://rakkhunnursinghome.com/user_img/files/29688866665.pdfIn PDF document text
    • https://www.domaine-vrignaud.com/ckfinder/userfiles/files/kuwigufano.pdfIn PDF document text
    • http://foto-recepty.sk/images/fotky/godopiwazoz.pdfIn PDF document text
    • https://coffeetuanvang.com/Images_upload/files/wadupisek.pdfIn PDF document text
    • https://homini.eu/wp-content/plugins/formcraft/file-upload/server/content/files/160b8c1f998d30---lomegafaruzitan.pdfIn PDF document text
    • http://poltinik.ru/userfiles/file/6552267714.pdfIn PDF document text
    • https://alrukn.co/userfiles/files/1998721596.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_off0000b888.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB888 16328 bytes
SHA-256: 83f4e3e426a8928098de079dad82df69481f3b37e8df35786ad42881b55c87f8
font_01_sfnt_off0000e2a3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE2A3 11416 bytes
SHA-256: d676780eaca685c99740757c536f9ea44df0795a2a2b0392f30fd24644c24ee5
font_02_sfnt_off0000fcfd.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFCFD 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1