Malicious PDF — malware analysis report

Static analysis result for SHA-256 423b52bbbfc034f2…

MALICIOUS

PDF

85.0 KB Created: 2021-09-01 16:46:28 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-16
MD5: b5b8fea27a7e1b003f9a182e56869de8 SHA-1: 1dab193c47c672d46bc78ca9aa91505043ed8d63 SHA-256: 423b52bbbfc034f2f36829041aab7f414a9d94ae05b184388fef92b25256258d
156 Risk Score

Malware Insights

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

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Numerous heuristics point to the PDF acting as a link farm, directing users to compromised websites hosted on various domains, some of which appear to be WordPress installations. The embedded URLs suggest a phishing or malware distribution scheme, likely leveraging a vulnerability within the PDF reader to execute a payload.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9934

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://queure.ru/uplcv?utm_term=how+to+repair+a+damaged+pdf+file+online PDF link annotation
    • https://provisionsinternational.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609daf206bec5---wodovixelo.pdfIn PDF document text
    • https://www.chesapeake-lighting.com/wp-content/plugins/super-forms/uploads/php/files/36262b42dcbb9ba5234bde9fd7a6e692/5219242381.pdfIn PDF document text
    • http://riskhedgetech.com/uploaded/file/210022714360d1b0871a836.pdfIn PDF document text
    • https://kaptenhoki.com/contents//files/98983402791.pdfIn PDF document text
    • https://nikken-engineer.jp/export/sd205/www/jp/r/e/gmoserver/8/6/sd0748886/nikken-engineer.jp/fckeditor/upload/file/rijubeneweso.pdfIn PDF document text
    • https://signaturetowerpune.com/wp-content/plugins/super-forms/uploads/php/files/hhs02firienih4b924u92k51q3/pajigajiwamijapufet.pdfIn PDF document text
    • http://irmascaritasdejesus.org.br/wp-content/plugins/formcraft/file-upload/server/content/files/16083bed01e39a---zizewife.pdfIn PDF document text
    • http://brighterhealthcare.co.uk/wp-content/plugins/super-forms/uploads/php/files/pucvv7ku5b83vcqu1a04ou0668/5545515958.pdfIn PDF document text
    • https://baileyelectrical.services/wp-content/plugins/super-forms/uploads/php/files/dem25m80genj2p02mkghd8ishs/21500784033.pdfIn PDF document text
    • https://www.davinci.dk/wp-content/plugins/formcraft/file-upload/server/content/files/160947b64c22f8---kapabujak.pdfIn PDF document text
    • http://feuerwehr-mittenwalde.de/mediathek/files/78465405385.pdfIn PDF document text
    • https://bio86.net/fichiers/47681568168.pdfIn PDF document text
    • http://dralituncer.net/userfiles/file/dirolifikizifixopufali.pdfIn PDF document text
    • https://ctapigroup3.com/contents//files/68858060091.pdfIn PDF document text
    • https://akdenizokullari.k12.tr/wp-content/plugins/super-forms/uploads/php/files/ql79bhmp3h52atn2khmrnl7da1/wugebatadegejixuwapukupoj.pdfIn PDF document text
    • https://fitnessrev.net/wp-content/plugins/super-forms/uploads/php/files/cn7ejg86d5miu769t9d4eq34fa/fijolekapix.pdfIn PDF document text
    • https://ccveg.org/wp-content/plugins/super-forms/uploads/php/files/ar5l31efkqflljr87v2dit839l/14486769358.pdfIn PDF document text
    • http://thunderstar.cn/userfiles/file/20210502135602293375460.pdfIn PDF document text
    • https://fitness-sport.it/userfiles/file/meginaxalebuvigigubin.pdfIn PDF document text
    • http://www.sarajevo-inn-grunewald.com/wp-content/plugins/formcraft/file-upload/server/content/files/16091cf5c3674c---59807861534.pdfIn PDF document text
    • https://www.golddustdental.com/wp-content/plugins/formcraft/file-upload/server/content/files/160fcf6264e99a---51398995236.pdfIn PDF document text
    • https://impariant-club.ru/wp-content/plugins/super-forms/uploads/php/files/b9e208a513b17883831eccbdac959e60/bojubotokevenofulamuba.pdfIn PDF document text
    • https://xn----7sbabak5acz7byau.xn--p1ai/wp-content/plugins/super-forms/uploads/php/files/588a08d4cc43a5991feb683967001cc4/puvexokupibiv.pdfIn PDF document text
    • http://danies.ru/ckfinder/userfiles/files/38056255514.pdfIn PDF document text
    • https://koparieshorvathbusz.hu/files/file/75266404089.pdfIn PDF document text
    • http://vuatoyen.com/uploads/userfiles/file/48437690152.pdfIn PDF document text
    • https://www.audifonosdoshoydos.com/wp-content/plugins/formcraft/file-upload/server/content/files/160911bd280632---rivaz.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_off0000e934.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE934 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0001014b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1014B 10748 bytes
SHA-256: 62a323cfdf43aa342572460211d345db6b6952a8d0df41b5bf1aa9943a6d4f8e
font_02_sfnt_off000119ba.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x119BA 17032 bytes
SHA-256: cc6caa641159080fd66ebf29cfeda031eeec9da350b4bafb04df3ea964a4e1a7

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