Malicious PDF — malware analysis report

Static analysis result for SHA-256 85481ec9c1a342a5…

MALICIOUS

PDF

74.7 KB Created: 2021-09-16 14:33:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-14
MD5: 53447e680c7d0acb1841fa5d271110f3 SHA-1: 65c0e553d1c74a44fa4a8431376cf837a6262cfb SHA-256: 85481ec9c1a342a5b59d8b52248b12f25a0fb386d87f8a494943cc450b362d56
156 Risk Score

Malware Insights

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

The PDF contains a link farm with numerous URLs pointing to other PDF files, many hosted on disposable or compromised domains. The ML classifier and ClamAV detection strongly indicate malicious intent, likely phishing or malware distribution. The presence of multiple PDF link farm heuristics confirms the structure is designed to obscure the ultimate destination and potentially evade detection.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9973

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 http://upakuika.com/img/file/pupijaj.pdf In PDF document text
    • http://ybshajiang.com/userfiles/file/2021-09-03/210903173307903944zujt9s8cn8f4.pdfIn PDF document text
    • http://webinaris.net/ckfinder/userfiles/publics/files/59127253055.pdfIn PDF document text
    • http://sineadstone.com/userfiles/file/12245623153.pdfIn PDF document text
    • http://facilitymanagementassociates.com/survey/userfiles/files/10363376523.pdfIn PDF document text
    • https://catequesisnavarra.org/guiarte_userfiles/files/58909373625.pdfIn PDF document text
    • http://jjburgerut.com/uploads/files/94705299148.pdfIn PDF document text
    • http://alde-pace.org/ckfinder/userfiles/files/vizesoruwukalupanuvofu.pdfIn PDF document text
    • http://bluebirdcanada.com/FileData/ckfinder/files/20210902_321FF074C57DFDDB.pdfIn PDF document text
    • https://dodatkireklamowe.pl/web/uploads/files/disepanamonugeg.pdfIn PDF document text
    • https://giasidaily.com/uploads/userfiles/file/winabomawotabomumorame.pdfIn PDF document text
    • http://www.hebrewforreadingcomprehension.com/content/5169031615.pdfIn PDF document text
    • https://amkboiler.com/wp-content/plugins/super-forms/uploads/php/files/e48lmr34r6ilekupnli2ngfmvj/fewusogulumozabuz.pdfIn PDF document text
    • http://www.xpresswedding.com/wp-content/plugins/formcraft/file-upload/server/content/files/16139e5efccfde---dekematusir.pdfIn PDF document text
    • http://aitrans.cn/UploadFile/file/F1202109120406591821.pdfIn PDF document text
    • http://aqcorth.specialty-match.com/upload/files/wefizujevebob.pdfIn PDF document text
    • https://yuktiedu.com/wp-content/plugins/super-forms/uploads/php/files/f14fbb77e13eec4d954c7c5b165defc6/magesixetajok.pdfIn PDF document text
    • https://www.grdr.org/paidel/ckfinder/userfiles/files/75550796547.pdfIn PDF document text
    • https://music-group-store.com/upload/files/15497208981.pdfIn PDF document text
    • http://opt-russtd.ru/data_center/upload_pictures/file/5274824940.pdfIn PDF document text
    • http://szjg.hu/images/file/wazazon.pdfIn PDF document text
    • https://momsgardenfoods.com/ckfinder/userfiles/files/kasovepotivevixafabaled.pdfIn PDF document text
    • http://gardensyellowcab.com/admin/images/file/fonujamesuzifan.pdfIn PDF document text
    • https://ketex.com/trcgp/ckfinder/userfiles/files/pejodaxob.pdfIn PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/A3Ryygt5BCM/uplcv?utm_term=band+games+for+androidPDF 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_off0000c289.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC289 16476 bytes
SHA-256: 03154e59bbfaec91e82c72bada1d59b90581f1b46869ed3c76d798a3202921ed
font_01_sfnt_off0000eced.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xECED 10608 bytes
SHA-256: 80394d411d3d1d0b1ec92a5401d3629e02486a6041b48b87a0fa120bc32aed39
font_02_sfnt_off000104e8.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x104E8 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1