Malicious PDF — malware analysis report

Static analysis result for SHA-256 77a9605eb174db76…

MALICIOUS

PDF

75.2 KB Created: 2021-09-21 05:56:30 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: caecba2cf797db6e9b235acc5e723f03 SHA-1: 93adff89409d779ab1bb575e84cdd88200344f19 SHA-256: 77a9605eb174db7675927f272c75497fe810f74a32bf0d006553434ededf52d0
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate the document functions as a link farm, directing users to numerous external URLs hosted on potentially compromised or disposable domains. The ML_NYX_PDF_MALICIOUS and CLAMAV_DETECTION heuristics strongly suggest malicious intent, likely related to phishing or malware delivery via the embedded links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9976

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://clumba-indoor.ru/files/files/51375206672.pdf In PDF document text
    • https://kakvkusno26.ru/wp-content/plugins/super-forms/uploads/php/files/8a2d7301c81f1a564fb09ebb4f8dd2d6/52488791777.pdfIn PDF document text
    • http://tjjjsh.com/uploads/files/mejezizozuk.pdfIn PDF document text
    • https://cheeselicious.net/UserFiles/file/ruzudatol.pdfIn PDF document text
    • https://quangtriasianwindow.com/uploads/image/files/49552621614.pdfIn PDF document text
    • https://maidintown.co.uk/wp-content/plugins/super-forms/uploads/php/files/19c7bbdbb8b25f49a7cb83a225e216d8/76792709133.pdfIn PDF document text
    • https://speakingparrot.com/upload/ckfinder/files/40771494498.pdfIn PDF document text
    • http://optimaglobal.net/ckupload/files/zesezavejevuki.pdfIn PDF document text
    • http://tai-yang.tw/taiyang/upload/file/85533483566.pdfIn PDF document text
    • http://wsm.hk/images/files/tizidewokojikedujolurosul.pdfIn PDF document text
    • http://warehousetraining.ie/images/rajujigavori.pdfIn PDF document text
    • http://ledspectrumthai.com/ckfinder/userfiles/files/ruwilileduratixaxokipi.pdfIn PDF document text
    • http://audiomaster.se/wp-content/plugins/formcraft/file-upload/server/content/files/161366b8297046---83600487467.pdfIn PDF document text
    • https://www.inkfactory.pk/wp-content/plugins/formcraft/file-upload/server/content/files/16148706c55763---tukuzoz.pdfIn PDF document text
    • http://festivaldeliteraturadepereira.com/wp-content/plugins/formcraft/file-upload/server/content/files/16131382fc8aa2---buvatorusudawefevowiruxu.pdfIn PDF document text
    • http://firesecurity.sk/userfiles/file/44473644335.pdfIn PDF document text
    • https://hamayeshniroo.com/shop/file/xizulojutelewor.pdfIn PDF document text
    • https://kalatranslation.co.uk/wp-content/plugins/super-forms/uploads/php/files/02cigm4bq5unjo8ar6lq2n702c/43469622685.pdfIn PDF document text
    • http://noithatdangcap.vn/app/webroot/uploads/files/lavenedugiradorofagomoxo.pdfIn PDF document text
    • https://polaria.cz/images/file/xumixef.pdfIn PDF document text
    • https://cardion.dk/gfx/fckimages/file/27772482483.pdfIn PDF document text
    • http://yanartekstil.com/firma/files/52291790407.pdfIn PDF document text
    • https://ntpuvoice.com/ckfinder/userfiles/files/jegodofinanuxogexobetuvi.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/FevRqgeaUVY/uplcv?utm_term=android+studio+set+icon+for+appPDF 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_off0000c22d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC22D 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000da3f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xDA3F 17224 bytes
SHA-256: fac30c355114cf6a7d788a59feb96088d7f0db3eb6faa565e02ab767ebb53e4a
font_02_sfnt_off0001066d.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1066D 10648 bytes
SHA-256: 65be3d02cade6104304bce9f97da9ddf1cea4acdc0fef99955f7db7c92bcb5be