Malicious PDF — malware analysis report

Static analysis result for SHA-256 f8dc405716f18210…

MALICIOUS

PDF

72.8 KB Created: 2021-09-03 04:24:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-23
MD5: c2be579c1c83d1706d6f728cc39161f9 SHA-1: 275ddf802a5371dcec62094b9653657d4aa654fe SHA-256: f8dc405716f182104f7728addc5d172e3d68bf74653eb1e1480d7226032000ce
156 Risk Score

Malware Insights

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

The PDF contains numerous links pointing to compromised WordPress sites, indicating a link farm designed to distribute malicious content or phish users. The ML classifier and ClamAV detection strongly suggest malicious intent. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9991

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://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/r3d1j4j2ivugn6d5sk4eaja9vi/futofozemek.pdf In PDF document text
    • http://www.nowsingapore.co.id/wp-content/plugins/formcraft/file-upload/server/content/files/160bb19791c3b3---44730322134.pdfIn PDF document text
    • http://thanglong.vn-greenenergy.com/ckfinder/userfiles/files/vejomesukimovuda.pdfIn PDF document text
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607c3dfd20b20---80526786784.pdfIn PDF document text
    • https://andrejc.si/files/file/turusorunibofa.pdfIn PDF document text
    • http://gardatrans.com/content/Files/68399684767.pdfIn PDF document text
    • http://odpadykj.cz/UserFiles/File/dewokemoxoxivipezidite.pdfIn PDF document text
    • http://obasekiestates.com/UserFiles/file/40782630974.pdfIn PDF document text
    • https://hyundainhapkhau.vn/upload/files/towabavux.pdfIn PDF document text
    • http://qunjl.com/userfiles/files/5757913137.pdfIn PDF document text
    • http://comicpapyrus.com/wp-content/plugins/super-forms/uploads/php/files/833de8ccca2ed91abab790ad54a6fdce/darigadepemodod.pdfIn PDF document text
    • https://valve-toho.com/userfiles/file/50923624462.pdfIn PDF document text
    • https://www.straightmyteeth.com/wp-content/plugins/super-forms/uploads/php/files/d029c998ab47086d6f75f04069cf8c8e/36326396890.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/161045ce0e170a---87620844457.pdfIn PDF document text
    • https://indacphuc.com/wp-content/plugins/super-forms/uploads/php/files/6hkrb4onsfgcoqqehdpdnp3vl5/34400369350.pdfIn PDF document text
    • http://www.logistiekverbeteren.nl/ckfinder/userfiles/files/litizonad.pdfIn PDF document text
    • https://andrejc.si/files/file/letekugeki.pdfIn PDF document text
    • https://claphamjunction.com.au/wp-content/plugins/super-forms/uploads/php/files/f19029657076896812c26ab44f691b18/tadapexazalufufamadedos.pdfIn PDF document text
    • https://wacee.net/wp-content/plugins/formcraft/file-upload/server/content/files/160ac024eb07f2---tigujegebu.pdfIn PDF document text
    • http://thuduchouse.vn/pics/file/44544384390.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/6naE_Nh8_CY/uplcv?utm_term=owl+solar+monitor+manualPDF 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_off0000b69e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xB69E 10348 bytes
SHA-256: 6c0db43cfaaee63edc44c56594682ab9806cde41d4309c12a597998148ca7820
font_01_sfnt_off0000ce05.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCE05 18656 bytes
SHA-256: d9393282a6bc0bd57527b44f2f826c4aca616a0e7fa089d4a5c586e4d648bf39
font_02_sfnt_off0000fe34.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE34 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1