Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8f1b3588dd83856…

MALICIOUS

PDF

81.5 KB Created: 2021-09-02 22:12:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-07
MD5: 76502e1e470981cc29130064816f8e64 SHA-1: 0cc498bf80e904da3022ea30734e67adbffc0550 SHA-256: a8f1b3588dd8385637340f2a359c5e0d9219f861a7f689b4dbe25a12c791f1c8
156 Risk Score

Malware Insights

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

The sample was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm, with many URLs pointing to potentially compromised WordPress upload directories. The PDF structure itself does not contain readable content, suggesting its primary purpose is to host these external links, likely for phishing or malware distribution.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9944

Heuristics 6

  • 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 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://cuisinescartier.ca/upload/editor/file/77951791818.pdf In PDF document text
    • http://rajskiewakacje.pl/userfiles/file/zutuxem.pdfIn PDF document text
    • https://superchills.com/userfiles/file/vorimudizature.pdfIn PDF document text
    • http://hi-reid-solutions.com/wp-content/plugins/super-forms/uploads/php/files/f6a64eb1bf6093fb1674d51f65a8432a/96333900360.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/61d16206598595952d5bb8931046c30c/43724082797.pdfIn PDF document text
    • https://agsposure.org/wp-content/plugins/super-forms/uploads/php/files/a82733316f85fa5983e34354341ca80e/vevabexovafi.pdfIn PDF document text
    • http://coffee33.ru/archive/file/sanumufufidisarev.pdfIn PDF document text
    • https://www.ptlittleflower.org/wp-content/plugins/super-forms/uploads/php/files/55bpp6nf92pc26r1p31jmqn7dj/zilagupomokokitokug.pdfIn PDF document text
    • https://webtraffic.ch/wp-content/plugins/super-forms/uploads/php/files/ivmlvsgd4bip4pgl3r1lof4t6h/36507773303.pdfIn PDF document text
    • https://championsforchildren.org/wp-content/plugins/super-forms/uploads/php/files/827a08f98ff5cb8d09942eae56f84c3d/75600829629.pdfIn PDF document text
    • http://www.hcibatiment.fr/wp-content/plugins/formcraft/file-upload/server/content/files/160a69da202bb8---tabakikexenobiwudesufu.pdfIn PDF document text
    • http://elosc.com/upFile/file///ITX202107280933057280.pdfIn PDF document text
    • https://ewms.vn/wp-content/plugins/super-forms/uploads/php/files/orobj3gefga8uaogrvnh5fhi0c/71667835136.pdfIn PDF document text
    • https://www.lavishlook.se/wp-content/plugins/super-forms/uploads/php/files/062441cfe49c0122c46f3f2b747ef668/likanituwaninilire.pdfIn PDF document text
    • https://sportli.co.il/wp-content/plugins/formcraft/file-upload/server/content/files/160830d098fd4b---vawofubero.pdfIn PDF document text
    • https://mk-promotions.com/ckfinder/userfiles/files/36929505143.pdfIn PDF document text
    • https://grand-forge.ru/wp-content/plugins/super-forms/uploads/php/files/3494dd8ed60630751adf81dd7bbc1627/rebokipefalik.pdfIn PDF document text
    • http://birons.net/wp-content/plugins/super-forms/uploads/php/files/328d4c8f29335b1515bba5b702f304df/64437174521.pdfIn PDF document text
    • http://asu.com.vn/wp-content/plugins/super-forms/uploads/php/files/np0ujkcegrt7r5i67pk8d4g8t9/mosokoguzakifa.pdfIn PDF document text
    • http://www.mostex.sk/files/articles/file/33247128468.pdfIn PDF document text
    • https://lawpropertyconsultants.co.uk/wp-content/plugins/super-forms/uploads/php/files/rdqv2fsdto921dc44ohepprtbc/16462512213.pdfIn PDF document text
    • http://sieckultury.pl/wp-content/plugins/super-forms/uploads/php/files/20269d3765982737fab511177f9e94c0/84384122115.pdfIn PDF document text
    • https://bf-pomosch.ru/wp-content/plugins/super-forms/uploads/php/files/7nbh4ue278gcn8dmikfu6g6ba2/jupuga.pdfIn PDF document text
    • http://kythuatviet.vn/uploads/userfiles/file/53243497007.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/3vuEKuznOb8/uplcv?utm_term=dimensional+tolerance+symbols+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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cee6.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCEE6 11036 bytes
SHA-256: a4d40679bcd0b4f37c918fdc8aec777ae11ca985eb4c5b13059eae2b298cf162
font_01_sfnt_off0000e863.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE863 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010075.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10075 17400 bytes
SHA-256: acf6e6771fcf51a9b25b55e1e4b9c2479a38a1e75d97a74b8e7d232d4ffca659
font_03_sfnt_off00012e40.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12E40 2064 bytes
SHA-256: 5221cc56e96b657ff7c15f49bf1fbf1b5222e15cd7ffd769ce953162a3e53832

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