Malicious PDF — malware analysis report

Static analysis result for SHA-256 858d7a2837e56305…

MALICIOUS

PDF

77.4 KB Created: 2021-09-01 06:20:59 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-12
MD5: 1a3b8fa8140b0173ff6399eb9b53a4da SHA-1: b3bd84db27eac34aaaca17416917c8483023f50b SHA-256: 858d7a2837e5630577e239a9fa53bd83a960bb07d6fef31b365385388d01865b
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF contains numerous external links, many pointing to compromised CMS uploads or disposable hosting, indicative of a link farm used for phishing or malware distribution. The ClamAV detection and ML classifier strongly suggest malicious intent. While no scripts were explicitly extracted, the PDF structure and embedded URLs are sufficient to infer a malicious attack pattern.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9943

Heuristics 6

  • ClamAV: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2528dad23a95d95-d2528dad23a95d95-10044376-0
  • 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=cowherd+and+parrott+funeral+home PDF link annotation
    • http://esipro.lu/userfiles/file/vunitiponevaxajefuf.pdfIn PDF document text
    • http://daoltrading.com/userData/board/file/99666524294.pdfIn PDF document text
    • https://gionggiacam.com/ckfinder/userfiles/files/lisib.pdfIn PDF document text
    • http://theydeserveastamp.org/wp-content/plugins/formcraft/file-upload/server/content/files/1606cb81c91ca8---67033245763.pdfIn PDF document text
    • http://healingtown.org/userData/board/file/towalogipedimepipenov.pdfIn PDF document text
    • http://autoshiftbid.com/fckeditor/userfiles/file/gamogalexagifa.pdfIn PDF document text
    • https://fitnessrev.net/wp-content/plugins/super-forms/uploads/php/files/n8vdbpvvlimbqjv1isi5g0br9e/82174159437.pdfIn PDF document text
    • http://luingpyrex.cz/foto/Image/file/lisuzit.pdfIn PDF document text
    • https://anctools.com/ckfinder/userfiles/files/zupodofegopejen.pdfIn PDF document text
    • http://volkshilfe-vlbg.at/images/content/files/45710300766.pdfIn PDF document text
    • http://kirakuramenandsushi.com/uploads/files/luwakezezep.pdfIn PDF document text
    • http://fontanarosaserigrafia.it/userfiles/file/16855729061.pdfIn PDF document text
    • http://www.stockholmswingallstars.com/wp-content/plugins/formcraft/file-upload/server/content/files/160bb3ab1e0268---bameronotuzavul.pdfIn PDF document text
    • https://www.alertgy.com/wp-content/plugins/super-forms/uploads/php/files/4ec0465dba9d1f7cc72c6ff99c87f369/6382785195.pdfIn PDF document text
    • http://www.alfainstal.pl/wp-content/plugins/formcraft/file-upload/server/content/files/160bfc5bde03cf---84028815293.pdfIn PDF document text
    • http://irollee.com/userfiles/file/pokinitane.pdfIn PDF document text
    • https://oknoplus-omsk.ru/wp-content/plugins/super-forms/uploads/php/files/c2a2e982efb736153fc6ee61e80f188a/xurupuxiluzugubowuxotabe.pdfIn PDF document text
    • http://sjanzee.nl/file/rokuwisuri.pdfIn PDF document text
    • http://ieeepes-thailand.org/app/webroot/files/files/jatuzekulo.pdfIn PDF document text
    • http://www.sunarozlem.com.tr/wp-content/plugins/super-forms/uploads/php/files/cu1jqq1s39u5fro7f26p0a0ue4/5975323737.pdfIn PDF document text
    • https://motiv8workout.com/up/files/60189128759.pdfIn PDF document text
    • http://emilymillerlaw.com/customer/3/d/9/3d947ad6ce2568d98b832ccf5548371bFile/betusesevejutemo.pdfIn PDF document text
    • http://begues.mobi/userfiles/file/wetakol.pdfIn PDF document text
    • https://lawina-radom.pl/files/file/gewekuma.pdfIn PDF document text
    • https://cosplay-expo.it/ckfinder/userfiles/files/kunixafis.pdfIn PDF document text
    • https://xn--b8qxb801j.tw/upload/files/54824063512.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_off0000c954.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xC954 17508 bytes
SHA-256: 2acaeb228764e38d6bc617e060811645d18275ae514f8856f04dd24038fad4a2
font_01_sfnt_off0000f66e.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xF66E 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_02_sfnt_off00010e85.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x10E85 10720 bytes
SHA-256: 727d12557856cb129a76f78150ccb6631e8b578c9391e8adae46884a99c8ecaa

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