Malicious PDF — malware analysis report

Static analysis result for SHA-256 05aa4685223b6281…

MALICIOUS

PDF

93.1 KB Created: 2021-09-20 10:59:07 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3)
MD5: 3ec815cd10cb11529e95d85714438c12 SHA-1: cde8580f02bb9879bc158df55f2c0193ca1ea9e2 SHA-256: 05aa4685223b6281137c2f93d2a5f13a1330f5e2dd26e2e25f80b2342c30e771
156 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The PDF file was flagged by multiple heuristics as containing a link farm and external URIs, with one heuristic specifically identifying it as a 'PDF SEO Disposable Link Farm'. The ML classifier and ClamAV also strongly indicated maliciousness. While no scripts were extracted, the presence of numerous URLs pointing to various domains suggests an attempt to lure users to external sites, likely for phishing or to download further malicious content. The authoring application 'wkhtmltopdf' is unusual for a malicious PDF, but the overall pattern of link distribution is consistent with malicious document lures.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9840

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://garglob.ru/uplcv?utm_term=hide+my+ip+android
    • http://jlm-kg.com/uploads/file/36091941499.pdf
    • https://cosonnguyenthanh.vn/webroot/userfiles/files/77629891874.pdf
    • https://ghnservizi.com/file/rujegusunow.pdf
    • https://langumeistras.lt/i/File/rudagasolujaxamupugugesu.pdf
    • https://marosme.ro/hirek/file/zugelemewiwab.pdf
    • http://twtqedu.com/userData/ebizro_board/file/48020422735.pdf
    • http://madmojo.com/fckupload/file/revupit.pdf
    • http://veterky.ru/ckfinder/userfiles/files/16218105899.pdf
    • http://desiaussies.com/ckeditor/uploads/files/worarimaxevopirafakinuwal.pdf
    • https://broadstripe.com/wp-content/plugins/super-forms/uploads/php/files/3b13656ad2aaece76ca728925462fc75/wibudumoxizapepazapuwogu.pdf
    • https://www.simcoerecovery.net/wp-content/plugins/super-forms/uploads/php/files/9pv3a1aehfkao4f3lluios962s/vutubivunotaki.pdf
    • https://songhong-thudo.com/img/files/22951536929.pdf
    • https://299-45.com/CKEdit/upload/files/52836808117.pdf
    • http://bugaboo-buffalo.eu/UserFiles/File/bakotaripufaxesupozi.pdf
    • http://shimamura-mail-order.com/userfiles/file/nowibegujarowexukopop.pdf
    • http://timocomputer.cz/files/file/kuvujukazaduz.pdf
    • https://livre-d-art.com/ckfinder/userfiles/files/4551789920.pdf
    • http://hotelbelleepoque.bg/userfiles/file/27902617113.pdf
    • http://www.tecnotrefg.it/wp-content/plugins/formcraft/file-upload/server/content/files/16135b65b44074---musoxe.pdf
    • https://thefencedocumentary.com/adminfiles/file/73885218254.pdf
    • http://760_709737661.mildmedia-dev.eu/uploads/userfiles/files/lipazazukedodeluguwusige.pdf
    • http://bxbrdh.marketsearching.com/upload/files/89921828284.pdf
    • http://autohondl.cz/userfiles/file/lezomonovukunejim.pdf
    • http://werder-ritter.de/UserFiles/File/33958453701.pdf
    • 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 5

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000d889.bin
a2dfbee1b9689d1fc530296293ea0e14e2feee0aac389e53d28ed0421eac4b58
pdf-font-stream PDF embedded font (sfnt) at offset 0xD889 16364 bytes
font_01_sfnt_off0000eeed.bin
2dd97fe805f90fcc8e040af17c1f6e840220f9fb0e17828d1d3dec8cd2022f4a
pdf-font-stream PDF embedded font (sfnt) at offset 0xEEED 2364 bytes
font_02_sfnt_off0000f951.bin
9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1
pdf-font-stream PDF embedded font (sfnt) at offset 0xF951 16792 bytes
font_03_sfnt_off00011163.bin
bd3aae2de41cfda6d9c6f32ff79bfc415e4b50783d758949d278feeacaef2662
pdf-font-stream PDF embedded font (sfnt) at offset 0x11163 24312 bytes
font_04_sfnt_off00014f03.bin
00e15c209c6da4f72efc5543c0c827199557a180fccc2c40136c42ce92da8a44
pdf-font-stream PDF embedded font (sfnt) at offset 0x14F03 10344 bytes