Malicious PDF — malware analysis report

Static analysis result for SHA-256 b31e775aa95a8de9…

MALICIOUS

PDF

84.7 KB Created: 2021-09-18 03:13:13 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 66b12a3d226e84459fe205f4608d2c86 SHA-1: 8fdb848f126c30c174e7d5f8ae621ff870facef1 SHA-256: b31e775aa95a8de96ccbc3fc32fc89548b293359af8b26d24c87af06aa7e11ca
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous embedded URLs, many of which point to file hosting locations on compromised websites, indicating a link farm designed to distribute malicious content. Heuristics like 'PDF_SEO_DISPOSABLE_LINK_FARM' and 'PDF_COMPROMISED_CMS_UPLOAD_LINK_FARM' strongly suggest this malicious intent. The ML classifier and ClamAV detection further confirm its malicious nature, likely as a phishing or malware delivery mechanism.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9974

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://catamma.ru/uplcv?utm_term=iqiyi+on+android+tv PDF link annotation
    • http://z-him.ru/userfiles/file/bubegiva.pdfIn PDF document text
    • http://ohmytour.kr/FileData/ckfinder/files/20210901_EFBEEE80337DDB9B.pdfIn PDF document text
    • http://chothuexehochiminh.com/userfiles/file/38361758148.pdfIn PDF document text
    • http://anpo.vn/upload/files/35335714547.pdfIn PDF document text
    • https://rotterdampools.com/contents/files/63921201043.pdfIn PDF document text
    • https://manhremhoangvan.vn/wp-content/uploads/files/lijub.pdfIn PDF document text
    • http://bastola.org/userfiles/file/97794658198.pdfIn PDF document text
    • http://wangguanhardware.com/userfiles/file/juzeguwurupinefod.pdfIn PDF document text
    • https://pecintajp.com/contents/files/80473821257.pdfIn PDF document text
    • https://granitabrasive.hu/editor_up/32303610935.pdfIn PDF document text
    • http://podhoru.cz/userfiles/file/5164602135.pdfIn PDF document text
    • https://dmddsgn.com/wp-content/plugins/super-forms/uploads/php/files/c38f6b7e7bd8cbfa8a69ddc0b0725fa6/jiwafosuxeja.pdfIn PDF document text
    • https://aquaticlandscape.com/wp-content/plugins/formcraft/file-upload/server/content/files/16137cb6708db8---65838844660.pdfIn PDF document text
    • http://baoveantam.info/upload/files/zigevidezidajusutawujo.pdfIn PDF document text
    • https://hotelcorona.ro/files/35744503702.pdfIn PDF document text
    • http://www.aunay-sous-auneau.fr/ckfinder/userfiles/files/lisejinuxudo.pdfIn PDF document text
    • http://blueyee.com/upload/file/100356213746.pdfIn PDF document text
    • http://ondamarinarest.com/upload/files/15945276260.pdfIn PDF document text
    • https://granitabrasive.ro/editor_up/jivowejegeleto.pdfIn PDF document text
    • https://greenlandpark.com/uploads/files/vepukazixurarupozujepu.pdfIn PDF document text
    • http://oa30us.com/userfiles/file/34994081615.pdfIn PDF document text
    • https://hunglivet.com/uploads/files/202109081428479885.pdfIn PDF document text
    • http://amwordpress.org/wp-content/plugins/formcraft/file-upload/server/content/files/16139be0d8ab9c---begalomunixupubif.pdfIn PDF document text
    • https://cemb.ca/upload/editor/file/tobedamipujinal.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_off0000d944.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD944 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_01_sfnt_off0000f15b.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF15B 10172 bytes
SHA-256: 9bf80cdd9b3da0b6a9cf52f6a17626b4c767f7fbeb6159282b9b37fb2fb7d136
font_02_sfnt_off000107ff.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x107FF 22872 bytes
SHA-256: dc0e76433154c194f7992d059dd4ac9350a4acfd9570a23c43b35e5d96354688