Malicious PDF — malware analysis report

Static analysis result for SHA-256 831b4f894d4e2d80…

MALICIOUS

PDF

96.7 KB Created: 2021-08-31 09:56:16 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 2e471767928faa0d15416d235f659025 SHA-1: d6d2773e4293e23b6912c9f8b9209428d7dc91fc SHA-256: 831b4f894d4e2d806ff80cdca77deb6d7f242250c2d5a6f15f23d226a07b674c
156 Risk Score

Malware Insights

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

The PDF file contains numerous embedded URLs pointing to various domains, many of which appear to be compromised or disposable hosting. Heuristics indicate this is a link farm designed to redirect users, consistent with phishing or malware distribution tactics. The ClamAV detection and ML classifier strongly suggest malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9928

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://catamma.ru/uplcv?utm_term=is+4+a+lot PDF link annotation
    • https://uniqrelation.com/userfiles/file/goponunakut.pdfIn PDF document text
    • http://mabifitness.it/userfiles/files/mugavas.pdfIn PDF document text
    • http://rc-modeller.se/images/file///24575555516.pdfIn PDF document text
    • https://nothingbutsafetyglasses.com/userfiles/file/nusivijefematuno.pdfIn PDF document text
    • http://www.majoriscambio.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/161043d9ad654f---61027967719.pdfIn PDF document text
    • https://assurancemauricie.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606da2f5f081b---lefusulalorizorige.pdfIn PDF document text
    • https://leganordavigliana.it/uploads/file/96701695342.pdfIn PDF document text
    • http://www.medicalalliedtraining.com/wp-content/plugins/formcraft/file-upload/server/content/files/16080b96cabb84---vitezivarudixuzi.pdfIn PDF document text
    • http://sgpeo.pl/users/file/40652122944.pdfIn PDF document text
    • https://daaeportrett.no/upload/file/45531399872.pdfIn PDF document text
    • http://xn--80aaa1acmiejxr6d7fg.xn--p1ai/data/files/6110964742.pdfIn PDF document text
    • http://aeskulap24h.de/wp-content/plugins/formcraft/file-upload/server/content/files/160fc71393c8f0---refugejeguxamekajamov.pdfIn PDF document text
    • https://www.businesswatchguardingservices.co.uk/wp-content/plugins/super-forms/uploads/php/files/tkhml2qlbsf2ue5c0minjv80ou/pogapotuvila.pdfIn PDF document text
    • https://fallsplat.se/file/32797164864.pdfIn PDF document text
    • http://learnersdigest.org/userfiles/file/486333075.pdfIn PDF document text
    • https://digireg.dk/upload/10271323682.pdfIn PDF document text
    • http://watdoenwevandaag.nl/upload/tewewep.pdfIn PDF document text
    • https://agape4u.org/userfiles/file/44315670915.pdfIn PDF document text
    • http://bjhtdszdh.com/v15/Upload/file/2021611251242457.pdfIn PDF document text
    • http://adhdadvisory.com/wp-content/plugins/formcraft/file-upload/server/content/files/160acb01a887a9---nageguxolud.pdfIn PDF document text
    • https://www.grandiosa.is/wp-content/plugins/super-forms/uploads/php/files/35ij0v73fdb27elrpkjnp0ndm7/sovoj.pdfIn PDF document text
    • http://traiteur-ribot.fr/userfiles/file/tatidetosasijexuwitoviwun.pdfIn PDF document text
    • https://takitech.hu/userfiles/file/zugijoxuli.pdfIn PDF document text
    • http://avtrak.ru/ckfinder/userfiles/files/ruxir.pdfIn PDF document text
    • https://petek.biz/resimler/files/30012516875.pdfIn PDF document text
    • http://mp-hd.de/data/aktualnosci_imgs/file/68944185594.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 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off000117c5.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x117C5 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00012fd7.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12FD7 18248 bytes
SHA-256: 3f6b180bdb0ebeb984f850d5e9438377301d749b5d63c70880277d2f7c9d55ec
font_02_sfnt_off00015f36.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x15F36 9700 bytes
SHA-256: 4681b50cf430165ae849269874bef96287da5bfe76d737a9bb0c2161e6f59eb9

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