Malicious PDF — malware analysis report

Static analysis result for SHA-256 2535f859fbcd71dc…

MALICIOUS

PDF

84.2 KB Created: 2021-08-17 01:46:57 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-24
MD5: 73c5e0b95e58ac8598bb43ad1811c6d9 SHA-1: 7266c92427b0cca756cb16fcec983f0a7831dd21 SHA-256: 2535f859fbcd71dc735c392a371630b205712f6f5b28371e92b30118eb20d739
96 Risk Score

Malware Insights

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

This PDF file was flagged by an ML classifier as malicious. It contains numerous embedded URLs, many of which point to compromised WordPress upload directories, suggesting an attempt to host malicious content or redirect users to phishing sites. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, indicating it's not intended for human readability but rather as a container for these malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9793

Heuristics 5

  • 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://crysiq.ru/uplcv?utm_term=hern%C3%A1ndez+sampieri+roberto..+%282010%29.+metodolog%C3%ADa+de+la+investigaci%C3%B3n.+mcgraw-hill PDF link annotation
    • https://3dreamstudios.com/wp-content/plugins/super-forms/uploads/php/files/4af05b32cd0a2ef9e3cad675ac69f208/silagenofegimot.pdfIn PDF document text
    • https://cottingham-group.com/cufiles/files/9616125039.pdfIn PDF document text
    • http://argra.rs/wp-content/plugins/formcraft/file-upload/server/content/files/160b9fecd0630b---sevuwifivowelimulude.pdfIn PDF document text
    • http://sictombbi.fr/ckfinder/userfiles/files/97307067462.pdfIn PDF document text
    • http://lawcab.ru/wp-content/plugins/formcraft/file-upload/server/content/files/1606c75a714c8b---zisazobu.pdfIn PDF document text
    • http://zonwering-belgie.com/ckfinder/userfiles/files/70108283092.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/16073d1b2765e6---jikeruvop.pdfIn PDF document text
    • http://www.ebsjosepirosamaria.com/wp-content/plugins/formcraft/file-upload/server/content/files/16095f1c44d729---tipejiwenufabufazorevajus.pdfIn PDF document text
    • http://onnetsolution.in/userfiles/file/pixijog.pdfIn PDF document text
    • https://gulertrafik.com/wp-content/plugins/super-forms/uploads/php/files/s3fcslseau3g7gro7rv80sivuq/70387867435.pdfIn PDF document text
    • https://toocapen.com/files/19899015766.pdfIn PDF document text
    • https://www.paparazzirestaurant.com.au/wp-content/plugins/super-forms/uploads/php/files/55f5a3220bd570a70b8b81e80acfa8dd/28643548583.pdfIn PDF document text
    • http://clearlakesd.org/wp-content/plugins/formcraft/file-upload/server/content/files/160a38cca78b81---82575092053.pdfIn PDF document text
    • https://gikguamerica.com/userfiles/file/luvovufuroxal.pdfIn PDF document text
    • https://smarttactic.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160f4b978d4461---12383198237.pdfIn PDF document text
    • https://menuiserie-sainte-anne.fr/userfiles/file/sasodadavowijorewa.pdfIn PDF document text
    • http://ceskylakros.cz/userfiles/file/40060090343.pdfIn PDF document text
    • https://uniqrelation.com/userfiles/file/jonegawavolasudekisiso.pdfIn PDF document text
    • https://dfa-finanz.de/wp-content/plugins/formcraft/file-upload/server/content/files/160e95a65c57aa---nivebis.pdfIn PDF document text
    • https://thehideawayresortpattaya.com/userfiles/files/kejinobegosodikufo.pdfIn PDF document text
    • https://promtong.com/promtong/temp/file/miwilolunosubora.pdfIn PDF document text
    • https://ksuskalology.com/images/file/7611560183.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ac41334aad8---89551460377.pdfIn PDF document text
    • https://www.pharmaright.ca/wp-content/plugins/super-forms/uploads/php/files/ab1uup01ei61idkoqrfg0sghsd/63539579706.pdfIn PDF document text
    • http://khunghinhdepphuctin.com/media/ftp/file/jafufebojino.pdfIn PDF document text
    • http://tlumacz-lipno.pl/pdrzewiecki/files/tovawebedajejugilo.pdfIn PDF document text
    • 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_off0000c7d5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC7D5 17776 bytes
SHA-256: 27482daf5f68398afb0f355606d381079ed40588f8700077cfd029c3d0190adf
font_01_sfnt_off0000f494.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF494 12236 bytes
SHA-256: 32b51f5cc5f8619616479e68861aecee68a47c7960d628df4fe15a95f3c2d1cf
font_02_sfnt_off00011126.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11126 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off00012937.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12937 16140 bytes
SHA-256: 00b1f632e8afe72716c8bcdb76b7901b56c060d1dc0f96f3f5c1b8373b85735b

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