Malicious PDF — malware analysis report

Static analysis result for SHA-256 513d8c441515941b…

MALICIOUS

PDF

82.4 KB Created: 2021-07-20 08:22:17 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-27
MD5: 4be967340a64e2b7eb4fbc02277dac4a SHA-1: ae7b72efd94533e0c789a38cde19cc38b874430f SHA-256: 513d8c441515941b99104b50e2e0ca7412559428a98b51067ace61ba4185db4d
216 Risk Score

Malware Insights

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

The PDF contains malformed streams and a high number of links pointing to compromised WordPress sites, indicating an attempt to distribute malware. The ML classifier and ClamAV detection strongly suggest malicious intent. The primary attack vector appears to be luring users to download further malicious content via these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9833

Heuristics 8

  • 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 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.
  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • 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://developmentassociationofnagaland.org/nbloom/fckuploads/file/40535098273.pdf In PDF document text
    • http://bomtvplus.com/data/board/file/20210625185923.pdfIn PDF document text
    • http://archerelectricsupply.com/userfiles/file/25036154515.pdfIn PDF document text
    • https://vashadvokat82.ru/wp-content/plugins/super-forms/uploads/php/files/247c311a1828746e7e2e674a0f333142/jemukuxawupofiret.pdfIn PDF document text
    • http://www.toeterloeh44.de/files/5754289776.pdfIn PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/01e036c8e3d1e7462ea37122435a23ee/8002349817.pdfIn PDF document text
    • https://www.sahabatkeluargahomecare.com/wp-content/plugins/formcraft/file-upload/server/content/files/160838bdd9b180---botoxometolorelupul.pdfIn PDF document text
    • https://chokysitohang.com/Uploads/userfiles/files/bixetus.pdfIn PDF document text
    • http://zamokugrofa.sk/admin/fckeditor/file/bufewojomat.pdfIn PDF document text
    • https://bentzendesign.se/wp-content/plugins/formcraft/file-upload/server/content/files/160721cb2c21e5---75243981372.pdfIn PDF document text
    • http://ip-golubev.ru/ckfinder/userfiles/files/safigutabi.pdfIn PDF document text
    • https://chicagoportablexray.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608e31699080d---zexotavekogutaguxu.pdfIn PDF document text
    • http://offerseir.com/basefile/offerseircom/files/18608424112.pdfIn PDF document text
    • http://burfel.ru/upfiles/files/72970957599.pdfIn PDF document text
    • http://hy-concrete.ru/d/files/69319368087.pdfIn PDF document text
    • http://ranaghatpchsschool.org/userfiles/file/82729249412.pdfIn PDF document text
    • http://foodchemsino.com/d/files/kunefilajapel.pdfIn PDF document text
    • http://evola.it/userfiles/files/lopegajezonetuvekejuv.pdfIn PDF document text
    • https://naseeha.org/wp-content/plugins/super-forms/uploads/php/files/0d55a2b175366f90cd5b6c649667569e/nadeti.pdfIn PDF document text
    • https://acronimocostanzo.com/userfiles/file/97229879436.pdfIn PDF document text
    • http://kwik-it.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1608107cf8a0bf---79113225572.pdfIn PDF document text
    • http://hotstamping.pl/files/file/31906039238.pdfIn PDF document text
    • http://www.rlktechniek.nl/wp-content/plugins/formcraft/file-upload/server/content/files/160a33554189ab---3695730238.pdfIn PDF document text
    • https://rowadalbyt.com/userfiles/files/81731512968.pdfIn PDF document text
    • http://www.heksan.com.pl/file/62668715924.pdfIn PDF document text
    • https://makemycake.gr/wp-content/plugins/super-forms/uploads/php/files/mrkp7nlsqgl27g91d7f1p3aj25/41611352354.pdfIn PDF document text
    • https://www.charityweiss.de/wp-content/plugins/formcraft/file-upload/server/content/files/160819a74c4614---nubidukulixoselowoje.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=geography+of+india+majid+husain+latest+edition+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_off0000dac1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDAC1 11328 bytes
SHA-256: a766e2952d9b0662117ccbb1bac642f036c5cfaede7056f873f9d75e73bb2ca8
font_01_sfnt_off0000f501.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF501 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010d13.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10D13 17124 bytes
SHA-256: d3877820139f68c0b63ae4b59c9ef45e7eb13ac4f9ed1da6522f533289dfa8fe