Malicious PDF — malware analysis report

Static analysis result for SHA-256 c81dbf18c4d3b238…

MALICIOUS

PDF

77.4 KB Created: 2021-07-05 06:15:21 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-09-13
MD5: 499c703710af09cdf26a985f7580560b SHA-1: 7f419661c51daa9b8e66efd032c2f908c307541a SHA-256: c81dbf18c4d3b238243869437d115d40565a5b756c96b26aa50c069c842c0c73
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs pointing to compromised websites and disposable domains, a common tactic for phishing or distributing further malware. ClamAV detected this file as 'Pdf.Phishing.Trojan', and the ML classifier also flagged it as malicious. The presence of multiple external URIs and link farm heuristics strongly suggests a malicious intent to redirect users to potentially harmful content.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9948

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 https://medsplus.us/admin/images/file/gebupufopegi.pdf In PDF document text
    • https://mamap.in/ci/userfiles/files/volufuk.pdfIn PDF document text
    • http://moveisgarciadigital.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160ad94eb9c033---48454670312.pdfIn PDF document text
    • http://vasvaripalmuzeum.hu/upload/file/mopemi.pdfIn PDF document text
    • https://transcendenceit.com/wp-content/plugins/super-forms/uploads/php/files/b017c123a0cef6a713ede7ce09dc7638/susubozuzuvonutumeviguraf.pdfIn PDF document text
    • https://humantouchtranslations.com/wp-content/plugins/formcraft/file-upload/server/content/files/1/160854a0256251---39811455999.pdfIn PDF document text
    • http://go-trec.com/wp-content/plugins/super-forms/uploads/php/files/s34eo4jamkkvh03hu13gnbcu0e/24125042955.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/uitp7venp2a4m6u1aajce4ov26/86310508743.pdfIn PDF document text
    • http://www.uvhk.com/wp-content/plugins/formcraft/file-upload/server/content/files/160be368b46d52---munewinorelutowekote.pdfIn PDF document text
    • https://www.jemelectric.com/wp-content/plugins/formcraft/file-upload/server/content/files/160d69a3f0c769---8257093336.pdfIn PDF document text
    • http://cabin4kids.org/clients/0/05/050cd0fff5f75fdfd14851583cc0de74/File/guxes.pdfIn PDF document text
    • http://xn--90ad5ackt1d.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/42f763f1d6d8521812e0fd4c27b1ca4b/85917562477.pdfIn PDF document text
    • http://www.next-conseil.fr/wp-content/plugins/formcraft/file-upload/server/content/files/1608fd8b663c4f---22265948004.pdfIn PDF document text
    • https://brusroom.com/wp-content/plugins/super-forms/uploads/php/files/5659e898d3169dc5e12ad81b6a628b17/85686558981.pdfIn PDF document text
    • http://argentum.com/wp-content/plugins/super-forms/uploads/php/files/n9e3i4bfd3qu8ktcmg53qr44o8/46516445443.pdfIn PDF document text
    • https://www.quatainvestimentos.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/160850af1a008c---zubatomojab.pdfIn PDF document text
    • https://thepetrichortouch.com/wp-content/plugins/super-forms/uploads/php/files/t07uecntld6ok5rl9uqsffl82e/33102343376.pdfIn PDF document text
    • https://kop-trans.pl/uploads/userfiles/files/42588149079.pdfIn PDF document text
    • https://blueridgelightingandcontrols.com/wp-content/plugins/super-forms/uploads/php/files/fd01860a2d1a6ba2d6746f998e753f8b/gijizamorovosibesoxa.pdfIn PDF document text
    • http://milcontabil.com.br/wp-content/plugins/super-forms/uploads/php/files/nfeo15k91llhvf3tks3pnvqv13/60410689348.pdfIn PDF document text
    • https://ddriu.hu/wp-content/plugins/super-forms/uploads/php/files/214837bb126f9dffa22ccaf0184f4844/kazegiwuvokisona.pdfIn PDF document text
    • http://maynenkhipuma.vn/quangbasanpham/app/webroot/upload/image/files/41117268770.pdfIn PDF document text
    • https://www.tangelo.no/wp-content/plugins/formcraft/file-upload/server/content/files/1607869090e3cc---wakepodomubitef.pdfIn PDF document text
    • http://closehorses.com/userfiles/file/64947668006.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/cv9VXjIrmdE/uplcv?utm_term=and+say+replyPDF 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_off0000cc3c.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCC3C 10172 bytes
SHA-256: 59f4dc13802c3e5d15c889915d3ac3a0614580214cc531d7622714bfc57b258f
font_01_sfnt_off0000e31f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE31F 17016 bytes
SHA-256: 062b7bc557182d1ac60bbde1331bb9cafe81d70e6f29410d78740e097f39cef3
font_02_sfnt_off00010f22.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10F22 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1