Malicious PDF — malware analysis report

Static analysis result for SHA-256 f6a6e75decb58f2e…

MALICIOUS

PDF

94.7 KB Created: 2021-06-29 10:41:37 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 7b92f019263f1c7e317e6bc65b6941b5 SHA-1: 478c07931ba1be3f1117061c80b903b8f859e967 SHA-256: f6a6e75decb58f2ec274df541c4676a8fa808ec810139747fe57bf15f64ff8c5
156 Risk Score

Malware Insights

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

The sample is a PDF document identified as malicious by ClamAV and an ML classifier. It functions as a link farm, containing numerous URLs pointing to compromised WordPress sites and other disposable hosting. These links likely lead to phishing pages or further malware downloads, indicating a malicious intent to redirect users to harmful content. The document body is heavily obfuscated and appears to be generated by wkhtmltopdf, providing no direct user-facing lure.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9941

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://ksnjl.com/userfiles/files/xizubugigupokinot.pdf
    • https://www.gs-gleichmann.de/wp-content/plugins/formcraft/file-upload/server/content/files/1609aa194c14e3---9569592745.pdf
    • https://www.finestkindcharter.com/wp-content/plugins/formcraft/file-upload/server/content/files/16077695850dc8---bubezobafadebexawuluto.pdf
    • https://langumeistras.lt/i/File/58571979663.pdf
    • http://alexhofford.com/temp/files/file/ligesigerezux.pdf
    • https://www.colours-of.com/wp-content/plugins/super-forms/uploads/php/files/uui3ierfn7nhgg4hpd8vlse6gq/52912672369.pdf
    • https://lymfologi.se/anvandarbilder/221/files/wolevujomadizogajivov.pdf
    • https://altonika.pro/files/fck/file/62752659338.pdf
    • https://www.sgestrecho.es/wp-content/plugins/formcraft/file-upload/server/content/files/1609c7355b7c8f---tosefiz.pdf
    • http://kaufdeinauto.de/wp-content/plugins/formcraft/file-upload/server/content/files/1607b0bc7e01ba---xeseguwiju.pdf
    • http://e-park.es/img/uploads/files/87755081531.pdf
    • http://brickchamber.com/ckfinder/userfiles/files/mofofozuwebekalapote.pdf
    • http://andreagarciam.com/wp-content/plugins/formcraft/file-upload/server/content/files/160764e8a266ae---47456626748.pdf
    • http://aggengr.com/uploads/CMS/file/56294411905.pdf
    • http://aeskulap24h.com/wp-content/plugins/formcraft/file-upload/server/content/files/1609c63f8e37d0---12642629515.pdf
    • https://www.sidertest.it/wp-content/plugins/formcraft/file-upload/server/content/files/16078855c68e7a---80443031145.pdf
    • https://isosklo.cz/uploads/pikuruwel.pdf
    • https://kompaspt1.com/contents//files/83534185976.pdf
    • http://fabrykakonwersji.pl/wp-content/plugins/super-forms/uploads/php/files/91b6d016115699d9d3c6579dd6ed998c/lixoweribinitez.pdf
    • http://www.1000ena.com/wp-content/plugins/formcraft/file-upload/server/content/files/160b9cd207f864---zedogusenejexuxopeledaj.pdf
    • http://cedresarquitectura.com/wp-content/plugins/formcraft/file-upload/server/content/files/160ad83e919830---92315679095.pdf
    • http://big-blue-bus.com/pics/fotos/1/file/pizowuxas.pdf
    • https://feedproxy.google.com/~r/skout/mBVl/~3/zMnd8XtcwSM/uplcv?utm_term=how+many+glasses+is+80+oz+of+water
    • 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_off0000f70a.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF70A 16792 bytes
font_01_sfnt_off00010f21.bin
d8fd737d030f881f9be1b38d3e3e8291a316467969ab474c02d977fb9b154721
pdf-font-stream PDF embedded font (sfnt) at offset 0x10F21 11140 bytes
font_02_sfnt_off00012931.bin
bfc7ce51a1a9b37382af61f0075eb0cdb972126da031002d338643432d80e6e4
pdf-font-stream PDF embedded font (sfnt) at offset 0x12931 16252 bytes
font_03_sfnt_off00013f0d.bin
c05640f680020e66813ade26421d249db08a015a167435b11328a8af3aca479f
pdf-font-stream PDF embedded font (sfnt) at offset 0x13F0D 17108 bytes