Malicious PDF — malware analysis report

Static analysis result for SHA-256 4a28c1657c200004…

MALICIOUS

PDF

95.0 KB Created: 2021-08-10 05:15:18 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-11
MD5: 218ca51e9d0b0c9c6863eb8e99d9b18a SHA-1: da7a6ce6b1d7c0193496b7236d101112ce52f03c SHA-256: 4a28c1657c200004b3093acea6836c9ad66af969989cf2cd6d50266be657bc48
196 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links, many pointing to compromised WordPress sites, suggesting a link farm designed to lure users to malicious content. The ClamAV detection and ML classifier strongly indicate malicious intent, likely for phishing or malware delivery. While no scripts were explicitly extracted, the PDF structure and URL patterns are consistent with techniques used to distribute second-stage payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9875

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 to algorithmically-generated URL high PDF_RANDOM_URL_LINK
    PDF contains a clickable HTTP(S) link whose host looks algorithmically generated (pronounceable-random labels) and whose path/query carries a long high-entropy token. This is the randomized-redirector pattern of malspam phishing lures — the visible document is only a prompt — not a PDF parser vulnerability.
  • 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://discoveryenglish.org/wp-content/plugins/formcraft/file-upload/server/content/files/16076a9b10aafe---solanixajanefevanezilak.pdf In PDF document text
    • http://www.kissdocs.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/160be34aa630f9---woxoxitazuvegel.pdfIn PDF document text
    • https://censcakmu.org/board/file/files/58654088523.pdfIn PDF document text
    • http://www.mywil.ch/wp-content/plugins/formcraft/file-upload/server/content/files/160a28ef05066e---rusipamametopafuluv.pdfIn PDF document text
    • http://mwflower.com/upimagesfile///sojeveb.pdfIn PDF document text
    • https://geneolock.com/locktactyuma/userfiles/file/89075612908.pdfIn PDF document text
    • https://relleno-acidohialuronico.com/wp-content/plugins/super-forms/uploads/php/files/b320d388f0992361f8b48d5d07a9c618/lefovixonedepem.pdfIn PDF document text
    • http://smithmurdock.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac62196d33f---kavujuxipomebatugubijebed.pdfIn PDF document text
    • https://conexkarvan.com/cache/fck_files/file/44712576499.pdfIn PDF document text
    • http://prodesign31.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608c0bc097e85---85365034206.pdfIn PDF document text
    • http://doublehappyvstheinfinitesadness.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607f73c5b716d---tebig.pdfIn PDF document text
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/f4194cebdd9605d3526994460d8f8e58/42746335013.pdfIn PDF document text
    • http://jeugdopdewetenschapsagenda.nl/wp-content/plugins/formcraft/file-upload/server/content/files/1607d150246f44---24128777739.pdfIn PDF document text
    • http://iwort.de/userfiles/file/50442316000.pdfIn PDF document text
    • https://resulgame.com/calisma2/files/uploads/84647984319.pdfIn PDF document text
    • http://xn--b1ahhafccpgkb2bxo.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/7cf05ec92ebf8f6c0bf9888974dbe065/poketoza.pdfIn PDF document text
    • https://www.digitalsofts.com/wp-content/plugins/formcraft/file-upload/server/content/files/160960181494dc---tuvezaxiwim.pdfIn PDF document text
    • https://gservicepz.com/wp-content/plugins/super-forms/uploads/php/files/22071e3764b8f03d52c61779e6a4d704/xowisifuti.pdfIn PDF document text
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160b054c2631ec---80945414188.pdfIn PDF document text
    • https://people11people.gr/uploads/File/sisibugodebupinofefuwixam.pdfIn PDF document text
    • http://hondaototananlongan.com/upload/files/12375803901.pdfIn PDF document text
    • http://villalapinetafavignana.it/userfiles/files/vogodarivemefa.pdfIn PDF document text
    • http://aaz.sk/editor_uploads/files/widuru.pdfIn PDF document text
    • https://canevastoilestjean.com/upload/editor/file/xomonagazogotagep.pdfIn PDF document text
    • http://huthamcauquanggiap.com/upload/files/fufafexoge.pdfIn PDF document text
    • https://travolution.travel/wp-content/plugins/super-forms/uploads/php/files/0f5d2235efe8e1a88aeddb2f0c8f4b2e/87372847618.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/DOqCt-cVA4I/uplcv?utm_term=oxford+new+science+in+everyday+life+class+8+book+pdf+downloadPDF 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_off00010c4e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10C4E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012465.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12465 11348 bytes
SHA-256: f78cd8df0a50cd59c944e6e82966270b225aed58cde78f417ecd7a23efc3772a
font_02_sfnt_off00013f18.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F18 17760 bytes
SHA-256: 61f2c30b260af75cf7f6c2ef8f1c8225510980b3d2a03a75b6fcd1a99bda7b4a