Malicious PDF — malware analysis report

Static analysis result for SHA-256 dc8bc893e4bec2e7…

MALICIOUS

PDF

85.7 KB Created: 2021-09-14 18:06:31 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 3a21411a0bc19b0fc37578c972aede5e SHA-1: 5f0b089b2755c239c7dc14e271c32df5d875cf77 SHA-256: dc8bc893e4bec2e799a8b2ef8aa0f2487904fc0cb79f1485009e6f221ae86748
156 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. It contains numerous external URIs and links to compromised CMS upload storage, suggesting it functions as a link farm or phishing lure. The presence of embedded URLs and the nature of the heuristics point towards an attack pattern involving directing users to external malicious sites, likely for credential harvesting or further malware delivery.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9980

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 https://krisoc.ru/uplcv?utm_term=redmi+note+8+pro+stable+update PDF link annotation
    • http://villaturri.it/wp-content/plugins/formcraft/file-upload/server/content/files/161307b2fc8709---39978066106.pdfIn PDF document text
    • http://jca-t.com/fck_image/file/69078058453.pdfIn PDF document text
    • http://irina-beha.com/ckfinder/userfiles/files/81021713298.pdfIn PDF document text
    • http://corising.info/sa_upload/userfiles/file/20210901135443.pdfIn PDF document text
    • http://sva-jeanroze.com/xmedia/file/pejelanoz.pdfIn PDF document text
    • http://a2kat.ru/userfiles/file/6706813015.pdfIn PDF document text
    • http://autofox.lt/ckfinder/userfiles/files/poxesifabubuwemusita.pdfIn PDF document text
    • https://weldingportal.it/userfiles/file/kisitojesijigekozow.pdfIn PDF document text
    • http://e-restauracion.com/app/webroot/files/uploads/files/pibejajexoroja.pdfIn PDF document text
    • http://dmn.ca/wp-content/plugins/formcraft/file-upload/server/content/files/1613043231c099---14617342330.pdfIn PDF document text
    • http://arcenevents.nl/site/upload/files/44408185189.pdfIn PDF document text
    • http://www.prieteniitehnicii.ro/documente/file/posedef.pdfIn PDF document text
    • https://noticky.net/akce/fotky/file/nixemesemuxovuvexukaxir.pdfIn PDF document text
    • https://monarchwinemerchants.com/wp-content/plugins/super-forms/uploads/php/files/1803ffa02f2c326333497ed47cd0ab3a/jikexekipo.pdfIn PDF document text
    • https://madeirashopping.com/userfiles/file/misemox.pdfIn PDF document text
    • https://celovechurch.org/wp-content/plugins/super-forms/uploads/php/files/1b435f9a7a80bee76d219072cfa33375/64795332158.pdfIn PDF document text
    • http://olgapolyakova.de/files/files/jixegonozurovumajazitoba.pdfIn PDF document text
    • https://atrax.eu/userfiles/file/39021234894.pdfIn PDF document text
    • http://pasted-radio.de/web/files/40628932620.pdfIn PDF document text
    • http://aescantabria.es/upload/fckeditor/file///sugojeturozuti.pdfIn PDF document text
    • http://barefoot.pl/userfiles/file/54950861587.pdfIn PDF document text
    • http://strahyi.ru/images/file/futitanujerogo.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_off0000e85a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE85A 18040 bytes
SHA-256: 0c3db1bfefca833d22e4d0a3477132c57f1adb5a2af76e72c87d1533f518cc90
font_01_sfnt_off00011782.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11782 11048 bytes
SHA-256: 7ed18ba72bb274a1231e5051c6b492f0a1323eaf53ce0b8300f42025ca8bb234
font_02_sfnt_off000130fe.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x130FE 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1