Malicious PDF — malware analysis report

Static analysis result for SHA-256 4b5d9e1c25483ede…

MALICIOUS

PDF

77.0 KB Created: 2021-09-06 06:13:41 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 360f2a8ac9e36bc00f27fb6a1612818b SHA-1: 53864ea7ee69cea49be63aa996eb33776c9ab636 SHA-256: 4b5d9e1c25483ede59c1e7bd94801b901afc99621cb1817eb8fa4ef52047a859
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised websites or disposable hosting, indicating a link farm designed to redirect users. The ClamAV detection and ML classifier strongly suggest malicious intent, likely for phishing or malware distribution. Although no scripts were explicitly extracted, the PDF structure and link farm behavior are consistent with techniques used to deliver second-stage payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

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://xn----8sbfeahwarn6ac1adp3fb2p.xn--p1ai/userfiles/file/19412104999.pdf
    • https://hondamienbac.vn/userfiles/file/88070989742.pdf
    • http://byecook.com/ckupload/files/tiwegarekevojumofepufuti.pdf
    • https://retentionstudentexperience.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a48d507e496---bewabedelixusikuvo.pdf
    • http://morgancountyoh.com/userimages/rozelozupovixefefut.pdf
    • https://estigotours.com/wp-content/plugins/super-forms/uploads/php/files/2ce5da18538022ed2689ecf171728e56/22855520841.pdf
    • http://pincailight.com/zk/UploadFile/file/2021062200545073499.pdf
    • http://sieuthibongda.net/ckfinder/userfiles/files/wuzezafatusifumaxudodaze.pdf
    • http://nhs-carpediem.com/clients/46367/File/jekekuvezega.pdf
    • https://nhahangthanghuong.com/uploads/files/74512857124.pdf
    • https://rhagro.com.mx/wp-content/plugins/super-forms/uploads/php/files/c79be238b136b6882d2d08741a9993d3/9900873865.pdf
    • https://www.goldenplanet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160c585e9aa566---bopovexavedepalanujeba.pdf
    • http://matstravel.ru/userfiles/file/26678836772.pdf
    • http://thanhlamresort.vn/wp-content/plugins/formcraft/file-upload/server/content/files/160c55ebce3839---52068743984.pdf
    • https://speeddating.lt/speeddating/ckfinder/userfiles/files/74441630909.pdf
    • https://gagiongvitgiong.com/ckfinder/userfiles/files/79136548601.pdf
    • http://sungwoneng.com/upfile_editor/2021/files/99369693547.pdf
    • http://pericosrentcar.com.mx/wp-content/plugins/formcraft/file-upload/server/content/files/160c5e6c229a7f---wisug.pdf
    • https://www.ideaklinik.com.tr/wp-content/plugins/formcraft/file-upload/server/content/files/1606fcd4175e05---fepid.pdf
    • https://plasy.com/uploads/file/76284926380.pdf
    • https://foulardfotografando.it/file/85625947410.pdf
    • http://yaeram.com/userData/board/file/25069520978.pdf
    • https://functionalmovement.gr/wp-content/plugins/super-forms/uploads/php/files/147c410b622a7e87485f11e0aba2ecac/tebibazasekeno.pdf
    • http://shreejians.com/userfiles/file/vimukefagadewopavuzod.pdf
    • http://host.keraladreamhomes.com/~viswabrahmathach/admin/fckeditor/editor/filemanager/connectors/php/userfiles/file/32659131499.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/3vuEKuznOb8/uplcv?utm_term=numbers+1-10+printable+pdf
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000cac7.bin
2d2c9282bb363585386a01341ceb11827e5da4bd3ef3547cc5bcaf6a3a01e290
pdf-font-stream PDF embedded font (sfnt) at offset 0xCAC7 10964 bytes
font_01_sfnt_off0000e406.bin
3fa2d62a7d13d3b88c5fc29263d5b6149fb492e4339cd30aa119407f633526e2
pdf-font-stream PDF embedded font (sfnt) at offset 0xE406 16540 bytes
font_02_sfnt_off00010e7d.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x10E7D 16792 bytes