Malicious PDF — malware analysis report

Static analysis result for SHA-256 71e86b4711c4eb81…

MALICIOUS

PDF

82.2 KB Created: 2021-09-18 01:47:33 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: c1e2587978f3c3d967f117d6d86b0414 SHA-1: b759e49f6fe84420d7fbcd2a6db544d7f21afd50 SHA-256: 71e86b4711c4eb8162aed83a4a3251271e64f522dc27a6f468613923b73cf83e
156 Risk Score

Malware Insights

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

The PDF contains numerous links, many pointing to compromised CMS upload storage, suggesting a link farm designed to distribute malicious files. The ML classifier and ClamAV detection strongly indicate malicious intent. The document body is heavily obfuscated and unreadable, providing no direct clues to its purpose beyond the presence of links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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://brakos.it/file/rabuxi.pdf In PDF document text
    • http://baocaosudanang24h.com/uploads/image/files/20393762577.pdfIn PDF document text
    • http://urdu-hadith.com/survey/userfiles/files/83704939702.pdfIn PDF document text
    • http://massvt.sk/editor_uploads/system/files/doveposalasuxitivejozup.pdfIn PDF document text
    • http://pasted-radio.de/web/files/batedurubegatuwed.pdfIn PDF document text
    • http://fundacjahfg.pl/upload/file/80297537054.pdfIn PDF document text
    • http://cuacuongiare.vn/upload/files/favututosujesifati.pdfIn PDF document text
    • https://www.lsv-wittlage.de/ckfinder/userfiles/files/mobopoto.pdfIn PDF document text
    • https://atlasautoglass.com/wp-content/plugins/formcraft/file-upload/server/content/files/16134a45e4fbf2---89075522407.pdfIn PDF document text
    • http://hosungtour.net/FileData/ckfinder/files/20210907_86F9A9AD9D4301BC.pdfIn PDF document text
    • http://enidental.com/userfiles/file/20210918065928.pdfIn PDF document text
    • https://yaofangpeixun.com/upload/files/49343182284.pdfIn PDF document text
    • http://fullerton.kopanramen.com/uploads/files/tibuguxudanug.pdfIn PDF document text
    • http://mdtrend.hu/files/file/9969094514.pdfIn PDF document text
    • https://www.kiakaha.gr/wp-content/plugins/super-forms/uploads/php/files/0r6kv4nkiu3ajn525dd0re3ht8/rivasidizaziminubuzokawi.pdfIn PDF document text
    • http://vtracauto.com/wp-content/plugins/formcraft/file-upload/server/content/files/1612f7dc09983d---54857908685.pdfIn PDF document text
    • https://westcoastmovers.ca/wp-content/plugins/super-forms/uploads/php/files/cc2jcjalgrlrper71c7ns7m50m/63788342661.pdfIn PDF document text
    • http://energosol.pl/images_cms/file/35968617144.pdfIn PDF document text
    • http://swhos.com/upload/files/piwakusagowadad.pdfIn PDF document text
    • http://trineckevzdelavani.cz/webpagebuilder/ckfinder/userfiles/files/30795336307.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/ngfLrbzwjls/uplcv?utm_term=vita+video+editor+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_off0000dd8e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD8E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f5a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF5A0 18128 bytes
SHA-256: 5eee4db54c57f4033544074ee87a8a1986d02520850fb9254c4756fa0fcf35d7
font_02_sfnt_off0001244e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1244E 10196 bytes
SHA-256: 9ee27e0621f58a054639cd41daee2bafee63f20159222116d403f8ab933b2410