Malicious PDF — malware analysis report

Static analysis result for SHA-256 8aaccc81abac3160…

MALICIOUS

PDF

87.6 KB Created: 2021-09-15 21:27:35 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 4922b88b36283fa40d05bbc404001bce SHA-1: 650f781b325d8d37803ba7fbd1167567c5114487 SHA-256: 8aaccc81abac3160ce61655c839f3d6744e46834ff640ed85dfe01c225a7bdcb
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The file was detected as malicious by ClamAV and an ML classifier, indicating a high likelihood of malicious intent. Heuristics identified it as a link farm on disposable hosting, with numerous external URIs pointing to potentially malicious content. Although no scripts were explicitly extracted, the PDF structure and embedded links suggest it is designed to redirect users to external sites, likely for phishing or to download further payloads.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9942

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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://klubbelgickychobrov.sk/editor_uploads/files/58931154805.pdf In PDF document text
    • https://safehouseservices.in/fckfiles/file/83638709628.pdfIn PDF document text
    • http://dayuntang.com/assets/uploads/ckedit/files/20210916015446.pdfIn PDF document text
    • http://thepokeluau.com/uploads/files/pimozebebeb.pdfIn PDF document text
    • https://mtmhomeschool4art.com/mycms/uploadedimages/editorUploadedImages/file/14144199531.pdfIn PDF document text
    • https://mandalaconfeccao.com.br/wp-content/plugins/formcraft/file-upload/server/content/files/1613f0a6aba815---zesozoxa.pdfIn PDF document text
    • http://xn--b1agjlwjc3g.xn--p1ai/ckfinder/userfiles/files/kalasikiwaxafejisaduvum.pdfIn PDF document text
    • https://nocnepal.org.np/ckfinder/userfiles/files/21478366569.pdfIn PDF document text
    • http://ancheng-medical.com/uploadfile/files/49520680984.pdfIn PDF document text
    • http://mfahk.com/upload/files/dototigidumeli.pdfIn PDF document text
    • https://megashina24.ru/files/files/wilaxilusefuzu.pdfIn PDF document text
    • http://monthclean.com/uploads/files/202109020557258627.pdfIn PDF document text
    • http://gostinica-domodedovo.ru/files/95408031089.pdfIn PDF document text
    • https://fcksa.com/ckfinder/userfiles/files/33193144900.pdfIn PDF document text
    • https://transport-vehicules.fr/userfiles/file/31481160496.pdfIn PDF document text
    • https://serrechevalier-skifun.com/imagesfile/pojugazeziwerabufonel.pdfIn PDF document text
    • http://www.tempshift.com/app/webroot/files/uploadimagesfile/6703708160.pdfIn PDF document text
    • https://kop-trans.pl/uploads/userfiles/files/62798060221.pdfIn PDF document text
    • https://impulsa.mantareys.net/uploads/plantillas/files/lizewekefu.pdfIn PDF document text
    • http://apsons.eu/files/file/61551753045.pdfIn PDF document text
    • http://bigcool.net/webroot/img/files/feburifisa.pdfIn PDF document text
    • http://xn--80aafbjcazdrhzgiddbbcsg4l.xn--p1ai/pict/file/75230693934.pdfIn PDF document text
    • https://certifiedmoversinc.com/wp-content/plugins/super-forms/uploads/php/files/b9bbd9cbdf36af1cda1822e543f9435b/45244792295.pdfIn PDF document text
    • http://akinmedikal.com/uploads/file/pizabuborojunodubobo.pdfIn PDF document text
    • https://feedproxy.google.com/~r/skout/mBVl/~3/DOqCt-cVA4I/uplcv?utm_term=emoji+font+3+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_off0000f059.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF059 18964 bytes
SHA-256: 85cd8a8334cd7f44d2639a9fef8eeebf8ec187626c9baf19dbb5a21b0c9e3468
font_01_sfnt_off00012211.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x12211 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00013a28.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x13A28 10356 bytes
SHA-256: b5fac7ce5978bdcfcedd29f69ca603b36815a9dc09e951e23b90a50dead484bf