Malicious PDF — malware analysis report

Static analysis result for SHA-256 81d9946331862698…

MALICIOUS

PDF

85.5 KB Created: 2021-07-17 14:29:09 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 81d9b91c31c5b6788a595e7d9df7067b SHA-1: 843a0fea923f99b3fa2c23dac83297432ffe82c1 SHA-256: 81d99463318626989b2f52d72fd1d791db7a5d7501e6ca67a0d4c725bd2f0ad6
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment T1204.002 Malicious Link

The PDF was flagged by ClamAV as Pdf.Phishing.Trojan and an ML classifier indicated a high probability of maliciousness. Heuristics identified it as a link farm pointing to compromised CMS upload storage and disposable hosting, suggesting an attempt to distribute malicious content or phish users. The document body was unreadable, but the presence of numerous URLs and the heuristic findings strongly indicate a malicious intent.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9930

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://www.sir.co.uk/wp-content/plugins/formcraft/file-upload/server/content/files/160795d7f6da11---gatitedupufegewepogudo.pdf In PDF document text
    • http://dok-vo.ru/userfiles/file/92101517795.pdfIn PDF document text
    • https://ceadersvalet.com/wp-content/plugins/formcraft/file-upload/server/content/files/1607a4f0745b6a---54304830382.pdfIn PDF document text
    • http://eugensa.lt/app/webroot/uploads/userfiles/files/21008319360.pdfIn PDF document text
    • https://anthonygillant.com/userfiles/file/7127562189.pdfIn PDF document text
    • https://theatresaucinema.fr/uploads/file/gixiwigido.pdfIn PDF document text
    • http://imbirimbir.ru/files/rawin.pdfIn PDF document text
    • http://vinag7furniture.com/app/webroot/files/editor_upload/files/84888041218.pdfIn PDF document text
    • http://dalaichau.com/files/47118586787.pdfIn PDF document text
    • http://unseenadventure.com/userfiles/file/37097354427.pdfIn PDF document text
    • http://www.wiz-fac.com/uploadImg/file/vexuwakakumisafikum.pdfIn PDF document text
    • http://www.caribbeandentist.com/wp-content/plugins/formcraft/file-upload/server/content/files/1606fd4e3d4e1b---95360292364.pdfIn PDF document text
    • http://www.deadclan.nl/wp-content/plugins/formcraft/file-upload/server/content/files/16079648d7f7d9---87514216648.pdfIn PDF document text
    • https://alphacleanwashing.com/wp-content/plugins/super-forms/uploads/php/files/51263828f69aac76bcabf3cf58f6f67d/xifimuwa.pdfIn PDF document text
    • http://www.publicitymailing.ie/wp-content/plugins/formcraft/file-upload/server/content/files/16092a83a02f25---titetawiguxodezeguwemaz.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/16074564c24939---toxiguxomatud.pdfIn PDF document text
    • http://furniture83.com/upload/files/lavaxizelepunet.pdfIn PDF document text
    • https://noks.cz/wp-content/plugins/formcraft/file-upload/server/content/files/160bc63d2ec2c6---bisamidom.pdfIn PDF document text
    • http://mnogonomerov.ru/uploads/file/zitofukopugu.pdfIn PDF document text
    • https://voolabs.com/wp-content/plugins/formcraft/file-upload/server/content/files/160c2f0dc81927---pukisekewibixeva.pdfIn PDF document text
    • http://www.cuerpomenteyespiritu.es/wp-content/plugins/formcraft/file-upload/server/content/files/160a249551a360---67744691011.pdfIn PDF document text
    • http://rulada.by/upload/editor/files/nuximaxavokuwesufazux.pdfIn PDF document text
    • http://atreve.eu/ubezpiecz/obrazy/file/lenugonivot.pdfIn PDF document text
    • https://feedproxy.google.com/~r/1eyvgo/aqOO/~3/BvfzZFkJO3s/uplcv?utm_term=mary+j+blige+haterationPDF 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 4

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d3eb.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD3EB 10596 bytes
SHA-256: 68bcd4a88233d0e3b18db3672170b48bdb5bb2234e70cb90cb003f7620c51fd8
font_01_sfnt_off0000ec02.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEC02 17636 bytes
SHA-256: 4ce4db05ae9b64ba39a81609d31faae9c28844630d75dd8df41d3f73dfae38de
font_02_sfnt_off00011aa1.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x11AA1 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
font_03_sfnt_off000132b2.bin pdf-font-stream PDF embedded font (sfnt) at offset 0x132B2 16164 bytes
SHA-256: fd494554c7a7a2c4488382a78096c535ff133766c7221992be4f6a58596b2467

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