Malicious PDF — malware analysis report

Static analysis result for SHA-256 31bf4bb3a6a0c3ff…

MALICIOUS

PDF

83.0 KB Created: 2021-06-30 03:02:58 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: e44bba88a6642a342172469b83b3a05c SHA-1: 1b3053746a7b647628db3c3072352cc1b8cd2505 SHA-256: 31bf4bb3a6a0c3ffc40fd5fc6ab16ee3037310e15de53684f078036ae5d2f59f
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 hosted on compromised CMS upload storage, with numerous links pointing to disposable domains. The document body is heavily obfuscated, preventing analysis of its specific content, but the overall structure and URL patterns suggest a phishing or malware distribution lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9955

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.adler-leitishofen.de/wp-content/plugins/formcraft/file-upload/server/content/files/160a3be6772714---texibixaponof.pdf In PDF document text
    • https://elicopter-de-inchiriat.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160abe780d1589---bakixa.pdfIn PDF document text
    • https://www.parkgest.ch/wp-content/plugins/formcraft/file-upload/server/content/files/1608f11aa4d8e0---xodakogox.pdfIn PDF document text
    • https://aarhuskortet.dk/images/file/suvonobasu.pdfIn PDF document text
    • http://www.sport-konyv.hu/userfiles/file/jesapoj.pdfIn PDF document text
    • https://www.andyselfstorage.co.uk/wp-content/plugins/super-forms/uploads/php/files/j6v89klp68f4cflcesjn0f949e/solexijegoruwofule.pdfIn PDF document text
    • https://olgapopovaphoto.com/wp-content/plugins/super-forms/uploads/php/files/19cfdf3b34775a82ea980ea958ab5029/nuxeperifufexu.pdfIn PDF document text
    • http://asdgolfclubtoscana.com/writable/public/userfiles/file/77511470984.pdfIn PDF document text
    • https://westcoastmovers.ca/wp-content/plugins/super-forms/uploads/php/files/7g6jt7et6cs4qp7nkrg01v2ug2/23931913292.pdfIn PDF document text
    • https://brunoamaranti.it/wp-content/plugins/super-forms/uploads/php/files/b3optq0ccm9moojens1r224jl4/bofarafijep.pdfIn PDF document text
    • https://cakenepal.com/userfiles/file/83791997790.pdfIn PDF document text
    • https://www.burit.net/wp-content/plugins/formcraft/file-upload/server/content/files/1606cf29ede5f6---28503324867.pdfIn PDF document text
    • https://amirep.com/wp-content/plugins/super-forms/uploads/php/files/ae7212ea9f2bdc784347a7fad8a92a3e/sonefuponirodo.pdfIn PDF document text
    • http://dbcasagayathottam.org/assets/uploads/cms_images/files/pugumaxeririzupeworinof.pdfIn PDF document text
    • http://9meclinic.com/ckfinder/userfiles/files/67932355167.pdfIn PDF document text
    • https://vuaship.com/wp-content/plugins/super-forms/uploads/php/files/g4gr3kmvhcgm52u62s6jbel7m8/9345211617.pdfIn PDF document text
    • http://mfplus.ba/wp-content/plugins/formcraft/file-upload/server/content/files/1608639b22af34---zusupagogiduxegoxijuve.pdfIn PDF document text
    • https://inchirieriavioane.ro/wp-content/plugins/formcraft/file-upload/server/content/files/160c32c53451ea---waxeb.pdfIn PDF document text
    • https://neoville.ru/wp-content/plugins/super-forms/uploads/php/files/fcb9d407229da21e2731659f0d88d3ac/7099383659.pdfIn PDF document text
    • http://trungnguyenjsc.vn/uploads/image/files/wikexojoda.pdfIn PDF document text
    • http://bahtiyardishekimi.com/fckfiles/file/7703278106.pdfIn PDF document text
    • http://modelkyujin.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bebd1524fba---buviponedasosulowa.pdfIn PDF document text
    • http://xn----7sbabaajmdfbk3ddf3azka3b6a2r.xn--p1ai/ckfinder/userfiles/files/valutov.pdfIn PDF document text
    • https://west-holding.com/userfiles/file/supixaberavefijibuda.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/A3Ryygt5BCM/uplcv?utm_term=thier+there+theyrePDF 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_off0000e5f7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE5F7 9680 bytes
SHA-256: 86207cfa8b1dc87363a7ca910c55238320cf7b9863d4f36109ba0c949642950c
font_01_sfnt_off0000fb2c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFB2C 16452 bytes
SHA-256: f2f57d32e1eb95515ca6c31e54809cfb437c469b1f6d9af406a5aefe15ef6dbd
font_02_sfnt_off000125a0.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125A0 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1