Malicious PDF — malware analysis report

Static analysis result for SHA-256 ac251caef02a89c4…

MALICIOUS

PDF

89.4 KB Created: 2021-10-18 02:44:55 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-11-25
MD5: 4ec8b81e09836ef873e3b89eef2c9392 SHA-1: c0b4ad80e8fa435f79a583aebd9166f867751ee2 SHA-256: ac251caef02a89c455c8ea757fc043ac060f0e9867af1f80102279f1b855350a
156 Risk Score

Malware Insights

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

The file was identified as malicious by ML classifiers and ClamAV, specifically as a phishing trojan. Static analysis revealed it functions as a link farm, with numerous embedded URLs pointing to potentially compromised or disposable hosting. The presence of a link to a compromised WordPress upload storage further supports the malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9835

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://nieruchomosciprzetargi.pl/files/file/63210446709.pdf In PDF document text
    • https://12shio1.com/contents/files/jetewurid.pdfIn PDF document text
    • http://repetitorebi.ge/userfiles/files/zatamupigejobibuzof.pdfIn PDF document text
    • http://www.bufolari.com/public/immagini/file/xononidenawesetuwetabid.pdfIn PDF document text
    • http://ip-malkov.ru/uploads/files/biboz.pdfIn PDF document text
    • http://beerskiboot.com/img/upload/file/26815211436.pdfIn PDF document text
    • http://velocimapper.com/webfiles/file/31329927524.pdfIn PDF document text
    • http://suncitygroup.ir/basefile/suncitygroupir/files/70650788887.pdfIn PDF document text
    • http://iiiemjobs.com/FCK_Editor_Images/files/8293307490.pdfIn PDF document text
    • http://palestraarkadia.it/userfiles/files/kijemubetaridevokusego.pdfIn PDF document text
    • https://mclandpin.com/calisma2/files/uploads/10602417506.pdfIn PDF document text
    • https://dusunceokulu.net/resimler/files/wamutitasejaj.pdfIn PDF document text
    • http://arenabilardo.com/data/_files/64443330864.pdfIn PDF document text
    • https://www.sabiamente.es/wp-content/plugins/formcraft/file-upload/server/content/files/1615c2d3303139---mudufexelidegaxiguta.pdfIn PDF document text
    • https://gadd-asso.org/userfiles/file/90600945755.pdfIn PDF document text
    • http://www.mediacomriccione.it/wp-content/plugins/formcraft/file-upload/server/content/files/1614ea4edf09ca---24357952564.pdfIn PDF document text
    • https://refundsrefunds.com/wp-content/plugins/formcraft/file-upload/server/content/files/161516a9e468c1---gokuguriwoloxe.pdfIn PDF document text
    • https://kimtuong.vn/isc/public/files/fckupload/file/fafazaditilovafu.pdfIn PDF document text
    • http://yigang-lin.com/uploads/files/202109232032105361.pdfIn PDF document text
    • http://mzch.pl/userfiles/file/34052753337.pdfIn PDF document text
    • http://renknh.com/ckupload/files/20258581559.pdfIn PDF document text
    • https://glamweddingdesign.com/userfiles/file/malokobixadodaroko.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/16141bb1e450ca---97986339686.pdfIn PDF document text
    • http://uekekb.ru/!upload/files/xubezorukapa.pdfIn PDF document text
    • https://stpeterscbs.ca/ckfinder/userfiles/files/82014247816.pdfIn PDF document text
    • http://neodentpetrosino.it/userfiles/files/dusilujaravejoxugujevafaz.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Gsjc/~3/4dZi1sgP-vI/uplcv?utm_term=pictionary+online+with+friendsPDF 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_off0000f4e4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF4E4 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off00010cfb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10CFB 10776 bytes
SHA-256: f6d60f6122c7e4050facd48316b6a2906711bd7de92319cdb89ac1585f2a73de
font_02_sfnt_off000125d4.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x125D4 19156 bytes
SHA-256: b112ffd4661689c1b8f2b3b1be9398958bfc215dc391502b41f213f25c756de3