Malicious PDF — malware analysis report

Static analysis result for SHA-256 71b8493d3a2276b6…

MALICIOUS

PDF

105.8 KB Created: 2021-06-26 09:24:51 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: ecc8ada295e1a0c438e023c21faacad9 SHA-1: f602910e8a5d35c656139bd530e3e810c4985cf3 SHA-256: 71b8493d3a2276b602cac7d47ccd3d11997ae8fe950d4c62ff5888b9f52933f5
156 Risk Score

Malware Insights

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

This PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple potentially compromised websites hosted on disposable domains. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, suggesting it's not intended for direct user reading but rather as a container for malicious links.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9930

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://alliance-ltd.com/userfiles/39530839397.pdf
    • https://big-cash.de/wp-content/plugins/super-forms/uploads/php/files/pr0jeu28h3rm0rhv20seojtfn2/493172464.pdf
    • http://anhuishangbiao.com/upload_fck/file/2021-6-21/20210621190201176107.pdf
    • http://www.musicmaestrodiscos.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160b886e5108bb---ruxeloroluzawafuburolig.pdf
    • http://accronline.com/userfiles/file/ziwasisezojorexababa.pdf
    • http://lisahyatthealth.com/wp-content/plugins/formcraft/file-upload/server/content/files/160a9221886020---repugo.pdf
    • https://tripleccompanies.com/wp-content/plugins/super-forms/uploads/php/files/3a0ff25792e12cafbe0c5dc50f2a5bc6/tugidezufumevasifok.pdf
    • http://tano-cable.com/d/files/mozebofozemadopalefo.pdf
    • https://webmodels.studio/wp-content/plugins/formcraft/file-upload/server/content/files/1608bfcb2a865c---22088869655.pdf
    • http://panyuchen.com/ckfinder/userfiles/site_eachfun_com/files/dozobenopuwinunofapimi.pdf
    • http://www.benvenutialmare.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ace812eccb7---65526551813.pdf
    • https://kuechentreff-schmid.de/wp-content/plugins/super-forms/uploads/php/files/h354h9h8d5hu6fo2hmpclhmvi6/zefuluvuriwotofofam.pdf
    • https://jfefood.com/wp-content/plugins/super-forms/uploads/php/files/03e3322ae4118a88395b508d27213ba0/fefijeduzodelalidisodi.pdf
    • http://fqcycpa.com/jingkelun/userfiles/files/20210609045454.pdf
    • https://cls-toronto.com/wp-content/plugins/super-forms/uploads/php/files/60fab39d8c99ced3b5472edb0b0dc1e3/xixedisiwe.pdf
    • http://akgikorea.com/file_upload/fck_upfile/file/gopomazijeviwenemikemida.pdf
    • http://europeanprofservices.com/wp-content/plugins/formcraft/file-upload/server/content/files/160cde42a11c52---78668853588.pdf
    • http://ajivikafinance.com/userfiles/file/dobabe.pdf
    • http://www.iqubz.com/wp-content/plugins/formcraft/file-upload/server/content/files/1608133fba8780---43352507966.pdf
    • http://anaminfo.com/attachfile/file/1079713287.pdf
    • https://yastudio.net/wp-content/plugins/super-forms/uploads/php/files/a2c584ff1600e79959c50f74fa6a6870/64527760142.pdf
    • https://feedproxy.google.com/~r/Uplcv/~3/1KS0DP0cxss/uplcv?utm_term=holby+city+episode+guide
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#
    • http://purl.org/dc/elements/1.1/
    • http://ns.adobe.com/pdf/1.3/
    • http://ns.adobe.com/xap/1.0/
    • http://ns.adobe.com/xap/1.0/mm/
    • http://ns.adobe.com/xap/1.0/rights/
    • http://dejavu.sourceforge.net
    • http://dejavu.sourceforge.net/wiki/index.php/License

Extracted artifacts 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off00012332.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0x12332 16792 bytes
font_01_sfnt_off00013b44.bin
b7cbc676c371fafdc6fe18fd3e5079fd725fa84de66cc1e73083d41dd843040d
pdf-font-stream PDF embedded font (sfnt) at offset 0x13B44 18408 bytes
font_02_sfnt_off00016bbe.bin
dbbe10af7941d97c32295be25cbdddbcd3611aef08f3a0985cf276d961002d4a
pdf-font-stream PDF embedded font (sfnt) at offset 0x16BBE 10668 bytes
font_03_sfnt_off000183df.bin
dc06733fb1b3e8baa4303a7b234726769048d67753183ec25fed266cd0fe6b8d
pdf-font-stream PDF embedded font (sfnt) at offset 0x183DF 16224 bytes