Malicious PDF — malware analysis report

Static analysis result for SHA-256 d9723ea652ad235b…

MALICIOUS

PDF

81.3 KB Created: 2021-09-24 07:01:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: 6058f77a98be4bae3786f2ea772e1046 SHA-1: 7aa6fbed4d47c65b23da65ad31ee418b12273956 SHA-256: d9723ea652ad235b12ed10467363d0f74771a2db11f1c4844709e98030830f5b
156 Risk Score

Malware Insights

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

The PDF contains a large number of links pointing to various domains, many of which are identified as compromised CMS upload storage or disposable hosting. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution through these links. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a vehicle for the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://chinese-wall.tw/upload/files/85788802439.pdf In PDF document text
    • http://motolargo.pl/userfiles/file/12121185331.pdfIn PDF document text
    • https://santehsevast.ru/userfiles/files/kinofaxubobiwedetudut.pdfIn PDF document text
    • http://luxlustry.ru/img/upload/3360506012.pdfIn PDF document text
    • http://www.sunarmisir.com.tr/wp-content/plugins/super-forms/uploads/php/files/jrdjpbru5kmq9a22gfv4rpj9p7/25629128289.pdfIn PDF document text
    • https://sandp-engineering.com/ckfinder/userfiles/files/44145463443.pdfIn PDF document text
    • https://valerart.com/ckfinder/userfiles/files/wigibax.pdfIn PDF document text
    • http://www.enjoyvaltellina.it/admin/ckfinder/userfiles/files/4244420013.pdfIn PDF document text
    • https://tour-paris-guide.com/cite_imgs/file/71819329096.pdfIn PDF document text
    • https://geneolock.com/locktactyuma/userfiles/file/dejotawivosiritepefixubij.pdfIn PDF document text
    • https://www.sistemkabin.com/ckfinder/userfiles/files/navadikazoj.pdfIn PDF document text
    • https://mantyobras.com/userfiles/file/pimupiguj.pdfIn PDF document text
    • https://equantumconsulting.com/files/files/zefukuxusedomudimot.pdfIn PDF document text
    • http://ptk-astana.kz/wp-content/plugins/super-forms/uploads/php/files/3e224f2171fa9dffba07a1503665d1c3/94500406911.pdfIn PDF document text
    • http://www.alcera.ca/userfiles/file/51876582307.pdfIn PDF document text
    • https://ventana-sur.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613fb444d5d67.pdfIn PDF document text
    • https://trompis-tondschungel.de/userfiles/file/67347197343.pdfIn PDF document text
    • http://adoriantarla.ro/wp-content/plugins/formcraft/file-upload/server/content/files/161486e4e23e05---98161754350.pdfIn PDF document text
    • https://oceanflowerhotel.com/uploads/image/files/defufogi.pdfIn PDF document text
    • http://espicycooking.com/files/file///zurijixolax.pdfIn PDF document text
    • http://mko-yug.ru/wp-content/plugins/super-forms/uploads/php/files/f276fbf7a96267abf2589a1173ad1884/xozagotofojunaxara.pdfIn PDF document text
    • http://www.sandzthabapanel.co.za/wp-content/plugins/formcraft/file-upload/server/content/files/1613d00db02539---gagatazeneniwuzuxox.pdfIn PDF document text
    • https://bushregenerators.com/userfiles/files/14925008993.pdfIn PDF document text
    • https://cailux.lu/userfiles/files/20876751289.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/3vuEKuznOb8/uplcv?utm_term=common+words+that+start+with+dPDF 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_off0000db16.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDB16 17400 bytes
SHA-256: b96d2b6d1ea165aad592dbb5cb928197ff6091da01f768d95908f57c51aeb39f
font_01_sfnt_off000107cc.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107CC 10452 bytes
SHA-256: 1e6e81e79ed4259058c20754282dc3e3ff870128f6579a31c717699e64427972
font_02_sfnt_off00011f5b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11F5B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1