Malicious PDF — malware analysis report

Static analysis result for SHA-256 c852831c02c65b5d…

MALICIOUS

PDF

89.8 KB Created: 2021-07-02 14:54:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-14
MD5: 68424e1eb38d5e38af64230b3dc8a6cd SHA-1: 918ba40815289ae865a4c7d7417b69e012ee9c44 SHA-256: c852831c02c65b5d5efb74e0c22793cb8630cbe2a3a58900f3b1eba611ea7035
156 Risk Score

Malware Insights

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

The PDF file was flagged by multiple heuristics as malicious, including a high-confidence ML classifier and ClamAV detection as a phishing trojan. It contains numerous links to compromised WordPress sites and disposable hosting, indicating a link farm designed to redirect users to malicious content. The document body is heavily obfuscated and unreadable, suggesting an attempt to hide its true purpose, which is likely to facilitate phishing or malware distribution through these external links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9902

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 http://xn--h49avwqct32ewe967crscpsaz7d.com/ckupload/files/95749284717.pdf In PDF document text
    • https://metroguards.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160c405227950f---40714459105.pdfIn PDF document text
    • http://www.holzbau-hoelzl.at/wp-content/plugins/formcraft/file-upload/server/content/files/160714e9d3a1bd---ninupododesox.pdfIn PDF document text
    • https://maloneslandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/16079c95b24793---bafibuzexeborarogukitu.pdfIn PDF document text
    • http://redwoodpwr.com/wp-content/plugins/super-forms/uploads/php/files/2fd13gm84gqr162f6s0v88gn10/36953849718.pdfIn PDF document text
    • http://makaifruits.com/wp-content/plugins/formcraft/file-upload/server/content/files/160aadbc36454c---48507236931.pdfIn PDF document text
    • http://nbpcpentecostalchurch.com/clients/65183/File/44918798865.pdfIn PDF document text
    • http://inlikeflintlogistics.com/wp-content/plugins/formcraft/file-upload/server/content/files/16075a87c68444---48845058256.pdfIn PDF document text
    • https://cls-toronto.com/wp-content/plugins/super-forms/uploads/php/files/085a0772d9f67ec1c77af266a5ec97f9/mupizudutaxaravogerasutar.pdfIn PDF document text
    • https://dienlanhbachkhoa.info/upload/files/nakokerupejuzewokutukobuf.pdfIn PDF document text
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/1609834e0a9ed2---19227285170.pdfIn PDF document text
    • https://gotoko.com/cmsv2/upload/files/vobotukuzijazivu.pdfIn PDF document text
    • http://www.jindatunnel.com/up_files/file/dukovinibi.pdfIn PDF document text
    • http://thaihotelsale.com/FileData/ckfinder/files/20210620_D4F5BEA033243470.pdfIn PDF document text
    • http://atol-res.pl/uploads/file/23382700485.pdfIn PDF document text
    • https://gservicepz.com/wp-content/plugins/super-forms/uploads/php/files/23c9eb03fe8b236d89ab85364d3922ed/83383119956.pdfIn PDF document text
    • https://dolnoslaskialarmsmogowy.pl/imgturysta/files/fuwebazawefikikumudus.pdfIn PDF document text
    • https://vestol.bg/files/file/58937124330.pdfIn PDF document text
    • http://accessiblevehicleservices.com/userfiles/file/ladipugakerumali.pdfIn PDF document text
    • https://www.3dreamchurch.com/wp-content/plugins/super-forms/uploads/php/files/0301a4dd782636711f1a4332b5fc8cb3/kagelubonipomapa.pdfIn PDF document text
    • http://www.thediethub.in/wp-content/plugins/formcraft/file-upload/server/content/files/16084169257c53---vevovejizumexewu.pdfIn PDF document text
    • http://limpiasol.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9536b7f358---supog.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/zMnd8XtcwSM/uplcv?utm_term=visually+impaired+meaning+in+englishPDF 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
stream_004_off0000ed9f.bin decompressed-pdf-stream PDF FlateDecoded stream at offset 0xED9F 18100 bytes
SHA-256: d76d708f6689bdc2f6b316d8a89fa80026f6fa044c056a99efb41ba1d1bf8572
font_00_sfnt_off0000c818.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC818 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000e025.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE025 3464 bytes
SHA-256: a8161c2f5ba9235eb51b4fcc43b6bb219725019365cb8d38f9ec25dfe5ce54ff
font_03_sfnt_off00010a65.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10A65 10804 bytes
SHA-256: c72f538e67731d93c5993d45adc0ce7a82ca622770cd543d225d189b4dab412f
font_04_sfnt_off000122cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x122CC 22052 bytes
SHA-256: cff067b6dc1f03f86ed903c0e60e6651e28032d7df5496669df362b17d9edd92

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