Malicious PDF — malware analysis report

Static analysis result for SHA-256 a8ac084d526a575e…

MALICIOUS

PDF

79.4 KB Created: 2021-09-13 08:57:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 78c4df3b29e94be47447afa8503fe787 SHA-1: 57dc90daa3029f48ac5b62589baf7426d7bb1c5d SHA-256: a8ac084d526a575e6ce2efaff42ff009a3a8202bc801ed505683501244c7f494
156 Risk Score

Malware Insights

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

The PDF file was flagged by a machine learning classifier and ClamAV as malicious, specifically identified as a phishing trojan. Heuristics indicate it functions as a link farm, directing users to multiple external URLs, some hosted on compromised WordPress sites. The presence of numerous external URIs and the 'PDF_SEO_DISPOSABLE_LINK_FARM' heuristic strongly suggest a phishing or malware distribution attempt.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9975

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://queure.ru/uplcv?utm_term=horimiya+vol+1+pdf PDF link annotation
    • https://rivieresoceanie.com/userfiles/file/32942045647.pdfIn PDF document text
    • http://www.commandinglife.com/wp-content/plugins/formcraft/file-upload/server/content/files/1613c1cc04ca94---69037202722.pdfIn PDF document text
    • https://halead.com/uploadfile/1630738625.pdfIn PDF document text
    • http://salespate.com/userfiles/file/23777701211.pdfIn PDF document text
    • http://sushikyototogo.com/uploads/files/tugudefire.pdfIn PDF document text
    • https://webrekruit.com/php_codes/Scott/VieauAssociates/code/userfiles/file/juvosinisodetumeloziwu.pdfIn PDF document text
    • https://hyundainhapkhau.vn/upload/files/91067804498.pdfIn PDF document text
    • https://maidintown.co.uk/wp-content/plugins/super-forms/uploads/php/files/81474ca5825307141c7a7ca76af2c769/71713554964.pdfIn PDF document text
    • http://andlupa.com/userfiles/file/159435948.pdfIn PDF document text
    • http://symbioticlifetech.org/attfile/fckimg/file///2021091324856_829996688.pdfIn PDF document text
    • http://architectureanddesign.it/userfiles/files/82278449544.pdfIn PDF document text
    • https://www.emmabowman.com/wp-content/plugins/super-forms/uploads/php/files/ce3b5e0c83e4d7e41af3bd9eaa3358fa/vinufemefime.pdfIn PDF document text
    • http://kerekagy.hu/UserFiles/file/85398012136.pdfIn PDF document text
    • http://ashioke.com/images/library/File/vebupivoxekogalare.pdfIn PDF document text
    • http://aldobini.it/userfiles/files/68108511745.pdfIn PDF document text
    • http://sculecuacumulator.ro/app/webroot/files/userfiles/files/2664643798.pdfIn PDF document text
    • http://xn--76-6kca8aqc6c.xn--p1ai/pic/userfile/90534468082.pdfIn PDF document text
    • http://clerus.hu/files/file/895844447.pdfIn PDF document text
    • https://marsanz.pl/uploads/fck/file/rilovuzis.pdfIn PDF document text
    • http://tz5168.com/uploadfile/image/2021/09/02/file/20210902_093334_189.pdfIn PDF document text
    • https://isuzuphonoi.com/data/dulieu/files/zezabanajuwaseda.pdfIn PDF document text
    • https://ikorti-iao.com/userfiles/files/79435485073.pdfIn PDF document text
    • http://thrifty-uy.com/files/others/zugivopidadoziku.pdfIn PDF document text
    • https://alsharqcc.com/userfiles/files/24437204156.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_off0000caaa.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xCAAA 10380 bytes
SHA-256: c75c4a702aa1820abb6d57db0cc4509ee4d75fd9dfcdcfa46d619b23fc3a0e0c
font_01_sfnt_off0000e221.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xE221 20460 bytes
SHA-256: 85277c91fbc347d6d6a507f5d201909610788455491367bb5e4d28e7b7dad7bf
font_02_sfnt_off0001180a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x1180A 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1