Malicious PDF — malware analysis report

Static analysis result for SHA-256 acfc9e7571e225d3…

MALICIOUS

PDF

89.3 KB Created: 2021-10-09 02:58:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-22
MD5: 2d24032a5be90d1ca2705524e88bcdb2 SHA-1: 4a5a6f970a46c9797c38c2bfaa30481b67ee6cb3 SHA-256: acfc9e7571e225d3e9475781168975156f1f1303af690342b7b94b7d05233b3b
156 Risk Score

Malware Insights

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

The file is identified as malicious by ML classifiers and ClamAV, with multiple heuristics indicating it functions as a link farm on compromised WordPress sites. The embedded URLs, such as the one hosted on plusbateria.com, are likely part of a phishing or redirection scheme. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9982

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 http://www.psstrecno.sk/wp-content/plugins/formcraft/file-upload/server/content/files/16134445519968---45072279414.pdf In PDF document text
    • http://almar-bus.pl/userfiles/file/16708666718.pdfIn PDF document text
    • https://efnnma.org/files/file/31157109894.pdfIn PDF document text
    • http://ysenb.kr/board/file/editor/file/vujukenareloba.pdfIn PDF document text
    • http://bestbelly.org/content/files/files/43743349118.pdfIn PDF document text
    • http://pttaccounting.com/userfiles/files/bofuru.pdfIn PDF document text
    • https://adesso-moosburg.de/images/file/30489495141.pdfIn PDF document text
    • https://jagamimpi.org/contents/files/kobosopilaraxevutagez.pdfIn PDF document text
    • http://plusbateria.com/wp-content/plugins/formcraft/file-upload/server/content/files/16155a371c7fd1---dojaginoxolunebibugalo.pdfIn PDF document text
    • https://siphouse96.com/wp-content/plugins/super-forms/uploads/php/files/a258c100b0eb9d1f3f5e0abacac6c953/tigawuxow.pdfIn PDF document text
    • http://udelimpa.es/ckfinder/userfiles/files/futaxopaj.pdfIn PDF document text
    • http://qdsenfeng.com/data/files/86438251236.pdfIn PDF document text
    • https://www.twibiotech.com/plugin/ce1/ckfinder/userfiles/files/pidobifosoke.pdfIn PDF document text
    • https://conexus-study-abroad-travel.com/ckfinder/userfiles/file/5565112661.pdfIn PDF document text
    • http://icsbc.ru/fuploader/file/nanorarinigixotodarafivo.pdfIn PDF document text
    • http://eventclub.pl/userfiles/file/70277276168.pdfIn PDF document text
    • https://atasuorganiktarim.com/upload/ckfinder/files/zetosatuvag.pdfIn PDF document text
    • http://whatifitspossible.com/ckfinder/userfiles/files/30586445474.pdfIn PDF document text
    • https://momsgardenfoods.com/ckfinder/userfiles/files/rozulevesirikiwile.pdfIn PDF document text
    • https://optical-axis.com/uploads/files/202109032001242494.pdfIn PDF document text
    • https://www.vasutaszeneiskola.hu/ckfinder/userfiles/files/99953266902.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/GLLx1DTH0VQ/uplcv?utm_term=another+word+for+good+writing+skillsPDF 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_off0000f4d3.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4D3 19652 bytes
SHA-256: 97897e9f93d78f2886fab229f3a97ab566b63950a1e38625dae359d8547a222d
font_01_sfnt_off00012780.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12780 10628 bytes
SHA-256: 63ccf8500d439c9ecf9a674959e2a004d365251e598060dc9d676f5f7d543ff8
font_02_sfnt_off00013f9b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13F9B 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1