Malicious PDF — malware analysis report

Static analysis result for SHA-256 f6e5034f444b7906…

MALICIOUS

PDF

93.4 KB Created: 2021-07-19 00:20:46 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: a659ae1d6d69e6583fdc3d30eb8ad4ab SHA-1: 9ca9336d5e8d58f6ea03c14b14d62a97d2d16d86 SHA-256: f6e5034f444b7906c868008f44054561fbf63254b6b02eb6c14035cf8ff5e698
156 Risk Score

Malware Insights

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

The PDF file 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 compromised CMS upload storage and disposable hosting. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather to host links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

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://www.a2zmedical.com.au/wp-content/plugins/formcraft/file-upload/server/content/files/1607cd0652e0af---83651576365.pdf
    • http://abacusnancy.com/userfiles/file/30258739180.pdf
    • https://ruta.hu/ckfinder/userfiles/files/68984700418.pdf
    • http://challendor.com/fckeditor/upload/file/bogenolibosamed.pdf
    • http://yishiweb.com/upfiles/files/20210610_041036.pdf
    • https://www.helpforbusymums.com/wp-content/plugins/super-forms/uploads/php/files/896f9315ca384271a04fe7f131fdccbc/45894742357.pdf
    • https://refour.dk/wp-content/plugins/super-forms/uploads/php/files/4bd99ca9e43aaeb8cad0765aabba1fd8/xiwunudozi.pdf
    • https://www.physioaktivkramer.de/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb10cc8ef1---loketewofafekalad.pdf
    • http://animalscipublisher.com/files/upfiles/file/30548286382.pdf
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/160abcda8f380e---46576579355.pdf
    • http://puppiesulove.com/clients/7/7f/7fa6d7836ea929643a3c23f4562b158d/File/leleviponetedizateduwopu.pdf
    • http://bjoybrands.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d1cc659a9d6---43060553351.pdf
    • https://www.taxikladis.gr/wp-content/plugins/formcraft/file-upload/server/content/files/1606f82644cbcb---zogivavupuzenobufimajoj.pdf
    • http://associacaoguainumbi.org.br/wp/wp-content/plugins/formcraft/file-upload/server/content/files/160a858956f3b1---68195825523.pdf
    • http://www.a-fairys-choice.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b408241d6cf---82752877937.pdf
    • http://arkystudio.eu/userfiles/files/jamazujifu.pdf
    • https://sancarspune.com/wp-content/plugins/super-forms/uploads/php/files/729174cf6a6bb716ac60526ec8d902cd/vapazabi.pdf
    • https://itexpertdog.com/upload/files/dixidurulalom.pdf
    • http://tutek.eu/userfiles/file/13251465272.pdf
    • http://olneyjune65.com/clients/d/dc/dcef5d22f85ec69f5810ba62c2e8cf46/File/daxakubobepivagowuvisagef.pdf
    • http://www.training4thefuture.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16090858b55525---40243461988.pdf
    • http://ddaengshop.com/ckupload/files/50001915555.pdf
    • https://www.harasportcenter.com/wp-content/plugins/super-forms/uploads/php/files/3sboviqpa01n8hsifbpnabr96d/64627868207.pdf
    • http://www.maarsehoveniers.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16083fb29bc911---78598499827.pdf
    • http://geoodwierty.pl/files/file/20705822606.pdf
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/1xuhb7AK25c/uplcv?utm_term=that+would+be+epic
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00010a60.bin
02f63f412f6e1bfb41cf4d08f01489ab7f76f591a99fc6b2bfbbf14fe145214a
pdf-font-stream PDF embedded font (sfnt) at offset 0x10A60 10528 bytes
font_01_sfnt_off0001224e.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x1224E 16792 bytes
font_02_sfnt_off00013a60.bin
f26c15d8d0c57d9bc0e5938bd3c10078e2004672f8155794774d86dbc473e77e
pdf-font-stream PDF embedded font (sfnt) at offset 0x13A60 17060 bytes