Malicious PDF — malware analysis report

Static analysis result for SHA-256 4fd21c368b339a51…

MALICIOUS

PDF

82.0 KB Created: 2021-09-06 11:38:10 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: e82db221cb8c5394050609e3cea86b07 SHA-1: 41e65323c8e2901d42d7b71c54b756e14fadb612 SHA-256: 4fd21c368b339a51a0ebe52889ac77f160992bfd27bd941eccdcc619f633d8ce
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous links to websites hosted on compromised WordPress installations, indicating a link farm designed to redirect users to malicious content. The ML classifier and ClamAV detection strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and embedded URLs point towards a common technique of luring users to external sites.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/16090806922da4---16613636664.pdf In PDF document text
    • https://regalcabs.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/16072be57f142a---11651726989.pdfIn PDF document text
    • https://too.kg/wp-content/plugins/super-forms/uploads/php/files/44e37c1fd4fc0f62fd0aafdec957ed77/58245156209.pdfIn PDF document text
    • http://ibookingkr.com/FileData/ckfinder/files/20210727_2C95779621389B07.pdfIn PDF document text
    • http://alibabashipping.com/userfiles/file/42158203750.pdfIn PDF document text
    • https://acornschoolcharleston.org/wp-content/plugins/super-forms/uploads/php/files/f78b54606d2d81643c2aedc1b04352da/58245098354.pdfIn PDF document text
    • https://mobistore.co.nz/wp-content/plugins/super-forms/uploads/php/files/19bba8dd8657ff202577cb4bab7cbe6f/59853773833.pdfIn PDF document text
    • http://for-rent-leuven.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bdfc21bea19---dozogi.pdfIn PDF document text
    • http://xn--80akij1ajew.xn--p1ai/wp-content/plugins/formcraft/file-upload/server/content/files/16131260ac901d---boxuxumanipe.pdfIn PDF document text
    • https://mymovingestimate.com/wp-content/plugins/super-forms/uploads/php/files/f18dd22d9db4029f770d3b94afc3f786/68446569550.pdfIn PDF document text
    • https://minegociomiweb.com/userfiles/file/98048132121.pdfIn PDF document text
    • https://relans-nn.ru/images/docs/file/27492043366.pdfIn PDF document text
    • https://g-ortho.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160c85276b9c1b---48238675383.pdfIn PDF document text
    • http://rusiuojigalvoji.lt/wp-content/plugins/formcraft/file-upload/server/content/files/1608601717b0fe---guvotopenefuwilikunu.pdfIn PDF document text
    • http://pulsrmedia.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607d92e005d58---91035818711.pdfIn PDF document text
    • http://bjerkelunden.org/content/files/userfiles/file///63138755176.pdfIn PDF document text
    • http://kasintorn.com/images/upload/files/lisizoguwi.pdfIn PDF document text
    • http://groupkaishan.com/d/files/vomatikasogutekow.pdfIn PDF document text
    • https://primax.fr/wp-content/plugins/super-forms/uploads/php/files/ce190m7s8e9eaud0244ml8hn57/82610153766.pdfIn PDF document text
    • http://woodlander.sk/grafika/file/wopasad.pdfIn PDF document text
    • https://www.gryf-wet.pl/ckfinder/userfiles/files/72377778176.pdfIn PDF document text
    • https://www.ezhealthcheck.com/wp-content/plugins/super-forms/uploads/php/files/1d8vcsbmfelvkvsgj3740sgkf7/64514928367.pdfIn PDF document text
    • https://beauty-full.ru/uploads/files/28092142125.pdfIn PDF document text
    • https://www.oasipizza.it/wp-content/plugins/formcraft/file-upload/server/content/files/1608141114841e---60700792632.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/LPIa9PGmDLg/uplcv?utm_term=pmbok+pdf+6thPDF 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_off0000dd50.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDD50 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f562.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF562 17520 bytes
SHA-256: f1badb0273513f186b2aa1f8c5d9900eabe5075ce2053b2d7d5d48904dc7177d
font_02_sfnt_off00012355.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12355 10360 bytes
SHA-256: 1d5fbe4a27cbc44690c2ca6b54d9b92a35620ee7541ca744a8f9e8075e11c24d