Malicious PDF — malware analysis report

Static analysis result for SHA-256 51990c36d4fe376f…

MALICIOUS

PDF

68.1 KB Created: 2021-09-29 03:38:04 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: bd05db25377a95831dc45c18f948f5f0 SHA-1: 9abb0783018b9ad4157dc984fbca5f624e9be805 SHA-256: 51990c36d4fe376fed58932ed354eda0d9debc9b320b434f1fe7e4a9d5a89165
156 Risk Score

Malware Insights

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

The PDF file was flagged by ClamAV as Pdf.Phishing.Trojan and by an ML classifier as malicious. It contains numerous embedded URLs, many of which point to compromised WordPress sites or disposable hosting, suggesting a link farm designed to redirect users to malicious content. The presence of 'utm_term' parameters in some URLs indicates a phishing or SEO-based lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9966

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://crysiq.ru/uplcv?utm_term=lyrical+pro+apk+download
    • https://njsolarpower.com/wp-content/plugins/super-forms/uploads/php/files/83696bc359a3a10a1b87dcab39edcbff/53943672742.pdf
    • http://yhbinternational.com/userfiles/file/22643018382.pdf
    • https://konzolstudio.ro/uploaded_files/file/637558428.pdf
    • https://rafaellopezehijo.com/upload/files/tagofogedis.pdf
    • http://dep14kirov.ru/userfiles/file/fiverofubofawakofik.pdf
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/1613b812171f42---rituworinip.pdf
    • http://jonme.net/ckupload/files/72450866664.pdf
    • http://koreanhotpot.com/uploads/files/4799112512.pdf
    • https://greengenome.in/admin/userfiles/file/zuwekokijagamuxonakuxoz.pdf
    • https://pestresolution.pt/site/upload/file/17131843122.pdf
    • https://hinodecoder.com/userfiles/file/xalomisirixixakuxat.pdf
    • http://naturalfurnish.com/userfiles/file/mesaxijumudekoxod.pdf
    • http://maslatalaia.com/userfiles/file/9096617047.pdf
    • http://totoumi.jp/upload/file/pupelenovamufuzoxumumakiv.pdf
    • https://www.fifatravels.com/wp-content/plugins/formcraft/file-upload/server/content/files/161319132c0d80---81431996971.pdf
    • http://www.gametimecatering.com/wp-content/plugins/formcraft/file-upload/server/content/files/161395ad62ea29---favizufeguloze.pdf
    • https://4cmedica.com/ficheiros_upload/file/92276594004.pdf
    • https://remini.hu/userfiles/file/zuxosubuzuzan.pdf
    • https://sitycare.com/FCK-UserFiles/files/92541138641.pdf
    • http://realfootball.gr/userfiles/file/87169356392.pdf
    • https://petroblend.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c149875498---7985791938.pdf
    • https://cheeselicious.net/UserFiles/file/nadovanikigizuloxojeruv.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_off0000ad66.bin
8aca617f3ba630eca505324cd0fc560676b7b2b636cfa807c3528d16518c777d
pdf-font-stream PDF embedded font (sfnt) at offset 0xAD66 15096 bytes
font_01_sfnt_off0000d3b7.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xD3B7 16792 bytes
font_02_sfnt_off0000ebce.bin
30878c4388d19304a2a05ef695a0296c132adc645514fec8eebc782423068fdf
pdf-font-stream PDF embedded font (sfnt) at offset 0xEBCE 10356 bytes