Malicious PDF — malware analysis report

Static analysis result for SHA-256 31e95fa810aeae23…

MALICIOUS

PDF

76.4 KB Created: 2021-03-11 10:27:03 +02:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 4.8.7) First seen: 2021-11-22
MD5: 15251ed44a84b665a1b6bf3fa3269da1 SHA-1: 23c4a9d8dfa6931f096904ba92a0001c2af43614 SHA-256: 31e95fa810aeae2332f4ea5042ed900b3bf60be2c0298e860793c0bfd7f548a4
186 Risk Score

Malware Insights

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

The PDF file contains a large number of external links pointing to various PDF documents hosted on disposable domains, indicating a link farm or SEO manipulation tactic. The ClamAV detection and ML classifier strongly suggest malicious intent, likely to distribute malware or phishing content through these links. No scripts were extracted, and the document body was unreadable, so the primary attack vector appears to be the embedded link farm.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9990

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
  • Small PDF contains mass external PDF link farm critical PDF_SEO_LINK_FARM
    Small PDF contains many clickable external PDF links, mostly clustered on one host. This matches generated SEO/link-farm PDF carriers used to route users into malicious or unwanted-software delivery chains, rather than a normal document citation pattern.
  • 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://golowaki.ru/123?utm_term=google+assistant+apk+lollipop+espa%25C3%25B1ol PDF link annotation
    • https://subafoxa.weebly.com/uploads/1/3/1/3/131379179/pegidav.pdfIn PDF document text
    • https://vojubewerele.weebly.com/uploads/1/3/4/0/134013512/0367421a1.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4413867/normal_5fd111dbaf2c1.pdfIn PDF document text
    • https://birugenok.weebly.com/uploads/1/3/4/6/134632973/797211.pdfIn PDF document text
    • https://vekatofe.weebly.com/uploads/1/3/0/7/130775682/minuwiwizu.pdfIn PDF document text
    • http://muzomabavima.medianewsonline.com/does_subway_calories_include_bread.pdfIn PDF document text
    • https://pidakulosa.weebly.com/uploads/1/3/4/3/134391257/3375265.pdfIn PDF document text
    • https://static.s123-cdn-static.com/uploads/4413968/normal_5fdd78cd4be8b.pdfIn PDF document text
    • https://dijatetobof.weebly.com/uploads/1/3/4/3/134322453/9366321.pdfIn PDF document text
    • https://zuvopiramalatug.weebly.com/uploads/1/3/5/9/135981479/kexamifig_tigerowati_pepogirel_vugokon.pdfIn PDF document text
    • http://xemokajoled.medianewsonline.com/rebakogexep.pdfIn PDF document text
    • https://romugazasemagop.weebly.com/uploads/1/3/4/8/134897733/4095673.pdfIn PDF document text
    • https://cdn-cms.f-static.net/uploads/4486534/normal_5fe887d54e5d0.pdfIn PDF document text
    • http://fosireditoj.mygamesonline.org/the_sims_3_ambitions_cd_key.pdfIn PDF document text
    • https://govonomuvilikiw.weebly.com/uploads/1/3/4/6/134620083/tamute_tetuk.pdfIn PDF document text
    • https://xudufuzed.weebly.com/uploads/1/3/0/8/130815664/jutoxufatajuresexore.pdfIn PDF document text
    • http://www.ascendercorp.com/In PDF document text
    • http://www.ascendercorp.com/typedesigners.htmlIn PDF document text
    • http://duribolatajofa.atwebpages.com/85000924791.pdfIn PDF document text
    • https://s3.amazonaws.com/tuxutedi/41977863593.pdfIn PDF document text
    • https://s3.amazonaws.com/mokamoba/nikon_coolpix_p520_user_manual.pdfIn PDF document text
    • http://dexivovadoxexo.myartsonline.com/hp_8600_clean_print_head.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/e083b2dd-6e46-4678-894d-eb49f568fe43/how_do_i_setup_my_netgear_wifi_extender_ex6120.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/73c103db-91ee-4541-948f-aafcd35f98b1/corian_countertop_dealers_near_me.pdfIn PDF document text
    • https://s3.amazonaws.com/tipikaxe/67719171172.pdfIn PDF document text
    • https://uploads.strikinglycdn.com/files/055ef196-d4d5-456f-9b96-f7e7965a0437/dinenetilepog.pdfIn PDF document text
    • https://s3.amazonaws.com/wiremeresegikon/cissp_official_study_guide_8th_edition.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://scripts.sil.org/OFLIn PDF document text

Extracted artifacts 2

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000ed02.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xED02 5196 bytes
SHA-256: 760dc2233b3f9956ae90e5298f2a31da775b76456e5fb1d17c63c84c36e60926
font_01_sfnt_off0000fe91.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xFE91 10452 bytes
SHA-256: 196a3c534094199d885fd97919946d544f82b39e80a98b5b6b6d7622891e33fa