Malicious PDF — malware analysis report

Static analysis result for SHA-256 538a5adc6b4cba0e…

MALICIOUS

PDF

97.1 KB Created: 2021-09-22 18:14:20 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 238694df66b01cd5da3f7c5d80e970f0 SHA-1: 3177c838cd02e3318d6ed0200a1b31297b19c364 SHA-256: 538a5adc6b4cba0e1113fec38a1da78616d82da5d16b2f5a983db77bb1e3bd81
156 Risk Score

Malware Insights

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

The PDF contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely phishing or malware distribution through these links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9965

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 http://elektrostroy.kz/ckfinder/userfiles/files/54852934003.pdf In PDF document text
    • https://hoya.hr/UserFiles/file/gamazilaninoferunami.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/16134115c07a74---tawakevekifuxasobomiduw.pdfIn PDF document text
    • http://begues.mobi/userfiles/file/kobidup.pdfIn PDF document text
    • http://3qbuy.com/CKEdit/upload/files/49551419637.pdfIn PDF document text
    • https://www.eecpowerindia.com/codelibrary/ckeditor/ckfinder/userfiles/files/dililebikaxivimisum.pdfIn PDF document text
    • http://xn--krmer-dnnebacke-1kb72b.de/files/file/xepuwumagifetotitajuse.pdfIn PDF document text
    • http://phutunggiahungoto.com/uploads/files/25598997601.pdfIn PDF document text
    • https://emergent-partners.com/wp-content/plugins/formcraft/file-upload/server/content/files/1614b423cf34bd---84556142142.pdfIn PDF document text
    • https://eliteplacementagency.com/uploads/files/xewovareb.pdfIn PDF document text
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/1614b0f989d21a---xalogar.pdfIn PDF document text
    • https://aymfly.com/aym_image/files/65194224316.pdfIn PDF document text
    • http://ukkies.be/userfiles/file/megipibagotizafaxemeripiz.pdfIn PDF document text
    • http://hellnocancershow.com/wp-content/plugins/formcraft/file-upload/server/content/files/16130737250a19---71219207256.pdfIn PDF document text
    • https://booburger.myagenda.cz/pictures/editor/files/zagogajovuwo.pdfIn PDF document text
    • https://gmonlinestore.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613ca2362f16e---velixuzaxarenesegefazav.pdfIn PDF document text
    • http://nwatchonline.net/userfiles/file/94045600800.pdfIn PDF document text
    • http://abbuffalowings.com/uploads/files/16698646458.pdfIn PDF document text
    • https://okna-kursk.ru/page_edit/_samples/userfiles/files/ruxirupexotefogediw.pdfIn PDF document text
    • http://imhkayseri.com/resimler/files/13972376376.pdfIn PDF document text
    • http://www.beverburcht.nl/upload/files/lufefevisotiluv.pdfIn PDF document text
    • http://kazuma.ru/ckfinder/userfiles/files/39087763130.pdfIn PDF document text
    • https://equalland.com/uploads/File/potikis.pdfIn PDF document text
    • http://le383.com/uploads/files/laraxi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/1KS0DP0cxss/uplcv?utm_term=minecraft+skins+androidPDF 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_off000117cf.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117CF 18260 bytes
SHA-256: 80f6560e95ec2f470fbb75f11bb80632f531da2ae6f5f9142d08136a14f60be6
font_01_sfnt_off00014661.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x14661 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00015e78.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15E78 10508 bytes
SHA-256: a155583ae39f26cee1215c410c90024949a9b1fcd8885fdd2e00112d05fbfb48